Would it make sense to improve pageload speed by serving smaller images from the database rather than make multiple HTTP requests given that the website is PHP driven?
I'm thinking of smaller page design elements, buttons, thumbnails for galleries etc.
No. Since:
A browser only communicates with the server via HTTP so you would have to pull them from a database, put them in HTTP, then return them to the browser
It is more expensive to pull large chunks of binary data from a database then it is to pull them from the filesystem.
If you want to make fewer HTTP requests, you can sprite the images, but don't do that with content images (which should have proper <img> elements with alt text).
also you can serve the images from multiple subdomains, so you can have more concurrent HTTP requests which could help speeding up.
No.
The user isn't directly connected to the database and you can't (well you can but it's so ugly I'm ignoring it) output the image data inside the HTML. They have to be loaded on separate requests.
If you store them in a database, you need something to access the database and then stream it out. It's actually seriously worse than just letting your httpd serve it. If a server hosts it, only the core server and the filesystem get touched. If it's in a database it's the core server, the connector to the language (eg mod_php), the language (eg php), the database connection and the filesystem (which the database is written on).
Keep it simple. Keep it as a file.
If you're drowning in requests:
If you're on Apache consider using a server like lighttpd or nginx. Massively more efficient on static/dynamic mixed environments. You can still keep apache or you can dump it altogether.
Shift your images off to a CDN like S3, Akami, etc. There are plenty of providers and it usually only works out a little bit more expensive than hosting (this is assuming you've got quite a lot of traffic).
It is possible, you can embed image in HTML using Data URI Scheme. But I doubt it will redeem, you will decrease number of HTTP requests, but images can be cached on client, so therefore you will greatly increase length of each response.
But, it will be faster to load those files directly from disc, not from DB.
The number of HTTP requests remains the same whether the browser loads images from a script that loads image data from a database or regular files. In fact, loading image data from a database rather than static files would probably introduce additional overhead.
If you're looking to reduce the amount of HTTP requests a browser has to make to load your documents, you should look into CSS Sprites.
You would save the overhead from the HTTP, but how would you insert the images in the html? Otherwise you have to still make an HTTP request to get the image.
If you serve the images as byteStream from the DB, you don't let browsers to cache the content. And if you use HTTP requests per image, you let them cache the content, but paying the price to do more requests. You have also to consider the time fetching the images from the DB and the time processing them!.
I think that your best option in this case, is put all the small images in just one file (sprite), and then use CSS to display them. That's what high load sites do. This way you just do one request and get all the images, the browser will cache the file and it will improve your perfomance. The price you pay is that you need to write more CSS but that's just plain text and the same number of files. It's a win-win situation :)
There are various ways to improve image performance in a website
Use an alternate domain just for static content. This has two benefits - cookies from your main domain are not sent with each request, and a separate domain gets it's own allocation of connections
Combine images into sprites
Configure caching correctly. Set far future expiry headers. Set the expiry header so that the image is not downloaded between visits to the site. When an image is requested, the ETAG can also be checked and if they match, then a 302 response is returned and the content is not downloaded again.
I don't see why streaming images from a database is going to better than from the file system. Your performance numbers are subjective I suspect because of caching.
Related
Theorizing here on how to get lightning fast media + prevent hotlinking and the <img src="data:image-kj134332k4" /> is coming to mind and more. Scrapers dont need our src and real clients need instant load (esp cell net). Considering the recent google https-everywhere move, this would drastically decrease handshakes as well.
What disadvantages are there to crafting lists such as ecom
categories/widgets/slideshows using data:image?
Is there any implications to extra KB of actual source code over serving vastly larger total page size?
Do ya'll prefer any PHP data:image gen script over another for parsing images as data as data at certain controller levels (leaving standard src images in other areas)?
Are there caching/CDN concerns? Would the parse wonk cache somehow? Seems not but im not cache expert.
Any guidance or case thoughts are much appreciated. Thank you!
Generally, the idea is worth considering, but in most cases the problems outweight the benefits.
It is true that these images won't be cached on the client side anymore. Especially Expires-based caching saves you tons of bandwidth.
As a rule of thumb I'd say: If these are small images that change frequently, embedding is a good idea. If images are larger and clients load the same image more than once in subsequent request, do by all means deliver images separately and put some effort into caching.
As for the other points:
Most browsers support this; however, some old IEs don't … so think of a fallback solution or be ready to get bug reports (may be neglible, depending on your user base.)
The number of SSL handshakes is neglible, if you're using HTTP keep-alive, which is standard. Follow-up requests do indeed require a new handshake, but if you cache properly (see next point) and maybe put static files on a CDN, this is no problem.
Read about caching, especially the Expires/Cache-Control headers and their friends.
If you decide to embed, you don't really need a generator script, embedded images are base64 coded image files; this shouldn't take more than 3 lines of code.
However, if you process/convert your images in PHP, there's even another disadvantage: Instead of statically serving them (maybe even from a different machine or CDN), images have to be on the same machine and go through the PHP engine, thus increasing the used memory of each process that serves a page with these images.
On my main page there is a big size image (~6 MB). It's kind of map.
I would like to store that image in user's browser even if they close browser or restart their PC, is it possible somehow?
That image is used in CSS file if it matter.
My hosting has small bandwidth, so I would like to store that image as long as I can on user's browser
Thanks for any tips.
There are a few options for this, some more convoluted than others.
The most cross-browser way is to make sure you set your cache headers to long cache times, and keep the URL consistent (similar to #Petah's suggestion).
Some browsers support the HTML5 File API. You could use JavaScript to store images here if it's supported.
You could also use the HTML5 AppCache (also with limited support), but this means you have to be careful about how you structure your application - because the HTML page will be cached forever until the cache manifest changes.
You can also serialise your image as a Data URL (fairly well supported) and store that string locally somehow (localstorage, cookies), but since cookies have small size-limits, and you wouldn't want to store 6MB in the HTML 'cos the page would take forever to load, this is probably not a great option.
You should look up caching best practices:
https://developers.google.com/speed/docs/best-practices/caching
http://msdn.microsoft.com/en-us/library/aa478965.aspx
http://developer.yahoo.com/performance/rules.html
You will have to set the correct HTTP caching headers for that image. With them you will tell the browser (and any proxies in between) to hold on to that image for as long as possible. But that will not guarantee that once user has that image that he will have it forever. It could be deleted from the cache for numerous reasons (user clearing the cache, browser evicting it, ...).
Start with this google search. If you want something more specific, you will have to tell us what web server you are using.
If you are worried about bandwidth, why not upload image to some image service (there are number of those around the Internet), and include its url in your css?
There are some concerns with these (free) services you should keep an eye for:
some image hosting services will block rendering of image (usually with image with text "not allowed to...") if
included on other sites like in stylesheets, forums posts... so you have to choose the one that dosen't do that
load time for image may vary dramatically if it is a free service, which is no big deal since once loaded in clients browsers, it will be cached
service may be temporarily unavailable which may cause you inconvenience with your clients
Try this.. Please change the href= to your image path and download= to the name of the file to be saved or you can leave it blank
<a href="imagepath/image.jpg" download="myImage.jpg">Click here to
download image</a>
Today I read some articles about compressing multiple JS and CSS files to one in order to lower the bandwith and HTTP requests. Is there analogical situation with the php files? Is it better to create master pages that include few PHP files(header.php,footer.php and etc)in order to have a well formatted and readable code than having just a large index.php?
PHP is run on the server, and as such, only the resulting HTML is sent over to the client. Keep your files separated for clarity, it doesn't make a difference in the HTTP requests or bandwidth.
Like Xeon06 mentioned, PHP is a server-side script, and doesn't affect a bandwidth, which is size the of the content transferred through HTTP. Size of the bandwidth based on HTML, CSS, JS, Graphics, Flash and anything client-side files. Because browsers cache these kind of files, it reduces the bandwidth, because browser will get the file content from cache and not download from server again.
If I were in your shoes, I would still use includes for headers, footers or whatever is common in most pages. It just makes it easier to maintain a content and code. For example, if you have a feedback form on all pages and you want to edit a field name, link or something else, it's easier to edit one file instead of "Find and Replace" through all files you have, which doesn't work well anyways.
I'm looking to cut down on HTTP requests for a mobile site and, as part of this, would like to utilise data URIs for sending images inline. Each page may load up to 12 thumbnails at a time, which are likely to change on refresh.
Basically i have 2 options; running base64_encode on the images on a per-request basis, or storing the encoded data in a DB and fetching that. The latter would involve a bit more work as the thumbnails may be updated periodically, so ideally I'd like the first solution, but only if the performance of base64_encode is such that it can handle encoding 12 thumbnails per page.
I'd be appreciative of any thoughts.
You should serve your image as plain image file, but from a separate domain. Because of how files are serve to the client, using a domain for images or medias could be more appropriate.
Also you should check caching server like Squid : http://www.squid-cache.org/
Just store in your database the file path.
Hope it will help you.
So I am working on something in php where I have to get my images from a sql database where they will be encoded in base64. The speed of displaying these images is critical so I am trying to figure out if it would be faster turn the database data into an image file and then load it in the browser, or just echo the raw base64 data and use:
<img src="data:image/jpeg;base64,/9j/4AAQ..." />
Which is supported in FireFox and other Gecko browsers.
So to recap, would it be faster to transfer an actual image file or the base64 code. Would it require less http request when using ajax to load the images?
The images would be no more than 100 pixels total.
Base64 encoding makes the file bigger and therefore slower to transfer.
By including the image in the page, it has to be downloaded every time. External images are normally only downloaded once and then cached by the browser.
It isn't compatible with all browsers
Well I don't agree with anyone of you. There are cases when you've to load more and more images. Not all the pages contain 3 images at all. Actually I'm working on a site where you've to load more than 200 images. What happens when 100000 users request that 200 images on a very loaded site. The disks of the server, returning the images should collapse. Even worse you've to make so much request to the server instead of one with base64. For so much thumbnails I'd prefer the base64 representation, pre-saved in the database. I found the solution and a strong argumentation at http://www.stoimen.com/2009/04/23/when-you-should-use-base64-for-images/. The guy is really in that case and made some tests. I was impressed and make my tests as well. The reality is like it says. For so much images loaded in one page the one response from the server is really helpful.
Why regenerate the image again and again if it will not be modified. Hypothetically, even if there are a 1000 different possible images to be shown based on 1000 different conditions, I still think that 1000 images on the disks are better. Remember, disk based images can be cached by the browser and save bandwidth etc etc.
It's a very fast and easy solution. Although the image size will increase about 33% in size, using base64 will reduce significantly the number of http requests.
Google images and Yahoo images are using base64 and serving images inline. Check source code and you'll see it.
Of course there are drawbacks on this approach, but I believe the benefits outweighs the costs.
A cons I have found is in slow devices. For example, In iPhone 3GS the images served by google images are very slow to render, since the images come gziped from the server and must be uncompressed in the browser. So, if the customer has a slow device, he will suffer a little when rendering the images.
To answer the initial question, I ran a test measuring a jpeg image 400x300 px in 96 ppi:
base64ImageData.Length
177732
bitmap.Length
129882
I have used base64 images once or twice for icons (10x10 pixels or so).
Base64 images pros:
compact - you have single file. also if file is compressed, base64 image is compressed almost to the size of normal image.
page is retrieved in single request.
Base64 images cons:
to be realistic, you probably need to use scripting engine (such PHP) on all pages that contains the image.
if image is changed, all cached pages must be re-downloaded.
because image is inline, you can not use CDN or static content web server.
Normal images pros:
if you are use SPDY protocol, at least theoretical, page + images + CSS will load with single request too.
you can set expiration on the image, so content will be cached from the browsers.
Don't think data:// works in IE7 or below.
When an image is requested you could save it to the filesystem then serve that from then on. If the image data in the database changes then just delete the file. Serve it from another domain too like img.domain.com. You can get all the benefits of last-modified, or e-tags for free from your webserver without having to start up PHP unless you need too.
If you're using apache:
# If the file doesn't exist:
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^/(image123).jpg$ makeimage.php?image=$1
Generally, using base64 encoding is going to increase the byte size by about 1/3. Because of that, you are going to have to move 1/3 bytes from the database into the server, and then move those extra same 1/3 bytes over the wire to the browser.
Of course, as the size of the image grows, the overhead mentioned will increase proportionately.
That being said, I think it is a good idea to change the files into their byte representations in the db, and transmit those.
To answer the OP Question.
As static files, directly via disk thru web server.
at only 100px they are ideally suited to in memory caching by the Web server.
There is a plethora of info ,caching strategies, configs, how-to's for just about every web server out there.
Infact - The best option in terms of user experience (the image speed you refer to) is to use a CDN capable object store. period.
The "DB" as static storage choice is simply expensive - in terms of all the overhead processing, the burden on the DB, as well as financially, and in terms of technical debt.
A few things, from several answers
Google images and Yahoo images are using base64 and serving images
inline. Check source code and you'll see it.
No. They absolutely do NOT. Images are mostly served from a static file "web server" Specfically gstatic.com:
e.g. https://ssl.gstatic.com/gb/images/p1_2446527d.png
compact - you have single file. also if file is compressed, base64
image is compressed almost to the size of normal image.
So actually, No advantage at all, plus the processing needed to compress?
page is retrieved in single request.
Again, multiple parallel requests as opposed to a single larger load.
What happens when 100000 users request that 200 images on a very
loaded site. The disks of the server, returning the images should
collapse.
You will still be sending The same amount of data, but having a Longer connection time, as well as stressing your database. Secondly the odds of a run of the mill site having 100000 concurrent connections... and even if so, if you are running this all of a single server you are a foolish admin.
By storing the images - binary blobs or base64 in the DB, all you are doing it adding huge overhead to the DB. Either, you have masses and masses of RAM, or your query via the DB will come off the disk anyway.
And, if you DID have such unlimited RAM, then serving the bin images off a Ramdisk - ideally via an alternative dedicated, lightweight webserver static file & caching optimised, configured on a subdomain, would be the fastest, lightest load possible!
Forward planning? You can only scale up so far, and scaling a DB is expensive (relatively speaking). Again the disks you say will "sp
In such a case, where you are serving 100's of images to 100000 concurrent users, the serving of you images should be the domain of CDN Object store.
If you want the fastest speed, then you should write them to disk when they are uploaded/modified and let the webserver serve static files. Rojoca's suggestions are good, too, since they minimize the invocation of php. An additional benefit of serving from another domain is (most) browsers will issue the requests in parallel.
Barring all that, when you query for the data, check if it was last modified, then write it to disk and serve from there. You'll want to make sure you respect the If-Modified-Since header so you don't transfer data needlessly.
If you can't write to disk, or some other cache, then it would be fastest to store it as binary data in the database and stream it out. Adjusting buffer sizes will help at that point.