Resize an image before user downloads it? - php

So this will no doubt come as a stupid question from an ignorant person, but I was wondering if there is any easy way out there of resizing an image BEFORE a user downloads it?
I am pulling in images from a 3rd party database, which I have no control over. I'm also not allowed to cache anything from it under their T&C.
They give a few different sizes for each image. But I am ending up resizing half of them on my pages with CSS.
So I was wondering if maybe using php or javascript or something! (I really have no clue do I), I could resize these images before my users waste time downloading much bigger versions.
The only reason I ask really, is that I know the Manchester United website kind of does it (with the aid of a piece of Adobe stuff I think), so I thought that maybe there might be something out there that anyone could use?
http://www.manutd.com/en/News-And-Features/Football-News/2011/May/Sir-Alex-Blackburn-reaction.aspx
http://www.manutd.com/~/media/64B766EE4A37488AA65DC7B08E5ABC1B.ashx?h=179&la=ar-SA&w=480&rgn=0,78,1200,524
-> 18kb compared to 160kb -> http://www.manutd.com/~/media/64B766EE4A37488AA65DC7B08E5ABC1B.ashx
(obviously I don't want the cropping technique)

If the images are coming from a server you don't control, the short answer is NO. You can't resize an image until you've downloaded it. Without caching a resized version, you are at the mercy of the 3rd party server. Unless you use a server side proxy program, yet this is probably more trouble than it is worth.
Yet as I've pointed out in the comments, http://www.manutd.com will resize their images for you. In the link h=height, w=width and rgn=region (left,top,right,bottom)
http://www.manutd.com/~/media/64B766EE4A37488AA65DC7B08E5ABC1B.ashx?h=80&la=ar-SA&w=120&rgn=0,0,1200,800
You only need the h and the w. If your h and w don't match the aspect of the image it will crop rather than skew. look at both of these. The image is 1200x800 aspect ratio 3x2
w=240, h=160 3x2 (whole image)
http://www.manutd.com/~/media/64B766EE4A37488AA65DC7B08E5ABC1B.ashx?w=240&h=160
w=160, h=160 1x1 (cropped)
http://www.manutd.com/~/media/64B766EE4A37488AA65DC7B08E5ABC1B.ashx?w=160&h=160
After I've played with it more, you can get by with just the width(w), and I'm assuming this also applies to just the height. (EDIT: yes it does)
Whole image, 480px wide...
http://www.manutd.com/~/media/64B766EE4A37488AA65DC7B08E5ABC1B.ashx?w=480
MORE EDITING: Understand, any time you see a '?' in a url, you are requesting a page from a program, and the stuff after the '?' are parameters for the program, and '&' seperates the parameters. The server at manutd.com is using a program to resize their images, just like a proxy program would resize images for you. If you did resort to a proxy program, if it was a decent one, it would take a link like http://YourServer.host/proxyProgram.php?img=imageHost.org/imageName.jpg&w=240&h=160 given a link such as that there are all sorts of server side solutions to resize the image.
Yet without a cache there is the possibility that you will resize the same image many times, and just the thought of that turns me off.
I'm gonna quit editing now!
Have fun!
Skip

Try using ImageMagick for PHP. It allows you to resize and modify images server-side. There are some examples here

Just off the top of my head, here's a pretty ugly way to get it done:
Create a PHP page that takes all of your requests. So instead of doing this...
<img src="http://other.domain/img.jpg" />
Do this:
<img src="http://your.domain/images.php?name=img.jpg" />
Then have your PHP page grab the image from the 3rd party site, and recreate it at whatever size you need:
$newe = imagecreatetruecolor($width, $height);
$old = imagecreatefromjpeg($fullpath);
$oldSizes = getimagesize($fullpath);
imagecopyresampled($newe, $old, 0, 0, 0, 0, $width, $height, imagesx($old), imagesy($old));
header('Content-type: image/jpeg');
echo $newe;
Some stuff that might trip this up:
If the T&C doesn't allow caching of images, they might not allow you to access their images with server-side code.
You'll have to adjust some of the code if you're doing other image types (gif, png)

This has to be done on the server. The technique used depends on what you're using on your server. If it's .NET, there is built-in functionality to handle resizing.

# Taze well server side, but he gets the images from another server and it seems you have not read it what he is doing and what he is allowed to do.
theoretically you could cache it (what you are not allowed to) on your own server, resize it with gdlib or imagemagick and give it to the user and then delete the copy from the server
but thats against the rules of the 3rd party

Related

PHP - Crop an image, and center the resulting image onto a background, using GD

I'm trying to make a simple app which gives a user a standard background/template image onto which they can place their logo/brand/whatever. I've had a look at a few jQuery plugins which allows the user to upload and crop an image, and most of them seem to work by posting the x and y coords, and the width and height, to the server.
I'm able to then use imagecopyresampled() to merge the image with the background image, but (a) the user's image seems to end up really skewed, even when I hard-code dimensions that I know should work, and (b) I need to position the uploaded image pretty much dead-center -- what's the best way to achieve this?
Any help? This is my first time using GD. I'll add my own code if required, but I'm messing with the different GD functions, so I've butchered the one I had before. Will reproduce it.
Thanks

PHP image resizing unknow source size, known output size

I am working on a site at the moment, that requires the admins of the site to be able to upload pretty much any size of image, I then need to find a way to get the image down to the size required for the front end of the end the site, all this needs to be done without know what size of image the user is uploading, but the image always needs to scale to 209x293 without looking awful.
Is this even possible?
You should argue with your client, to forget that rule(accept ANY image), and accept rather, only images in that proportion, or better, you can use a tool to crop the image, forcing the user to crop an image in your needed resolution.
Jcrop is a library in Jquery which can help you a lot if you want to create that cropping feature.
Don't know your precise requirements, but since you tagged it with CodeIgniter, you can check out the Image Manipulation Class which has everything you need to do the job.
Not knowing the size of images before uploading is, you know, quite a common problem...Just be careful of the MAX SIZE, which is set in your php.ini.
You might find useful also the page on file uploading right in php's manual.

Recognize image with PHP

I run a site with lots of small images (www.iconfinder.com) and would like to develop a feature that can compare and recognize images. A user should be able to upload an image (icon) and then the site will respond with information about the image if it's in the database.
What is the approach to finding similar (or the same image). I know I can compare md5 of the two images, but I also want be able to find matches if the are scaled.
This is a good start if you are interested in looking at doing it in PHP:
http://www.intelliot.com/blog/2008/03/sorted-directory-listing-image-resizing-comparison-and-similarity-in-php/
There probably aren't a lot of languages LESS suited to this task than PHP. You should really look for an image comparison library with a C compatible API and figure out how to glue that into your PHP application.
Identical images can be checked with an md5sum, but detecting if somebody uploads a scaled image, which displays the same thing as the other is very hard. This requires digital image processing.
An approach is to scale down all images to a certain width (say 100px). Then check a few coordinates for the color. If another image matches a big part (say 80%), it might be the same image.
But if the image is lighter... this won't work.

Question about image thumbnail performance in PHP

I have a function in PHP that resizes images into a thumbnail, my image upload script takes an uploaded image and runs this function to resize the image if it is wider then 700px it then also runs the function 2 more times to create 2 different sized thumbnail images, so there is a total of 3 images saved each time a user uploads an image. My resize/thumbnail function is called 2 times for the thumbnails and an occasional 3rd time if the file is to wide in dimensions.
Now this resizing function uses getimagesize( ) to get the dimensions, so my uplaod script calls this function, then the resizing function uses the getimagesize( ) function 2-3 more times to make other sized images.
I am thinking that I should just pass the dimesions onto the resize function since I get them in the uploading process?
My real question is, is getimagesize( ) a resource hungry functon, would it be best to use it at least as possible or is calling it a few times when 1 image is uploaded fine?
Just a tip/precausion, I asssume you're using GD functions. When creating more than one thumbnail, the usual bottleneck is wrongly implemented image resizing functions - each time reading the original image and then saving the resized one. A better way is to load the image once, and use the image resource to make all thumbnails with imagecopyresampled - don't only pass the dimentions of the image to the function - pass also the GD reference. Thay way your original file gets loaded only once.
For something that runs only on upload, it shouldn't bother so much. Uploading is not a action where the user expects super fast response. Premature optimization is the root of all evil.
That being said, getimagesize() is not particularly costly, but if you can call it just once do so. But I don't predict that much of a speed increase. The costly part of your script is the image resizing itself.
It's not particularly resource hungry - it has to open a file and read the image header.
Don't go out of your way to optimize it away - if it's easy, do it. Otherwise, wait and see where the real bottlenecks are in your application before optimizing.
The best thing to do is to profile your scripts.
Instead of theoretical answers which may not apply to a specific situation, you get a real answer and it is really instructive.
Also, with this habit, you will be able to :
discover bottlenecks
make the difference between a micro optimization and a major optimization.
I personally dev. on Windows and deploy on *nix.
On my dev dox, I use xdebug + WinCacheGrind to read the results.
I could not live without them. :)
http://elrems.wordpress.com/2008/02/12/profiling-php-with-xdebug-and-wincachegrind/
I don't think the uploading part should be where you resize the image. You should resize the image at a later time as a cron job. You can use a third party application like imagemagick or some other resizing application to resize images. That way you save time on the front end. You can run the resize job every 5 minutes or so.

How to resize linked images dynamically in PHP?

On my site I have given an option to user to choose thier profile image
Type link of an image
Image is a url link, and first I want it to resize to 400x300 (image's original size doesn't matter), and then display it on my web page.
Something like below:
<img src="http://mywebsite.com/resize.php?image=http://someotherurl.com/upload/image2.jpg&width=400&height=300" />
anyone knows this kind of script, please tell me how to solve this issue.
Thanks
A recent post:
https://stackoverflow.com/questions/1302464/php-image-resize-my-upload-script
has some code and comments that may give you some pointers. Otherwise may I suggest
http://www.white-hat-web-design.co.uk/articles/php-image-resizing.php.
Good luck!
If you have the GD extenstion, you can use imagecopyresampled (the documentation also features some examples). However, if the image to be resized is large and there is a low memory limit on your server, you may run out of memory.
I don't have ready to use source code, but it should look like:
Load image pointed by image parameter into object of ImageMagick (or other graphics library).
Resize it.
Send content to output stream.
Optionally you could:
Check if loaded file is image (plus other validation checks).
Save resized image on disk and serve it from disk next time (if you do it often).
Check docs of you favorite graphics library used in PHP for details.
Good luck!
Use the Class called - class.upload.php.
Find it at: PHP Classes
We use it at all times in many of our work.
The name is deceptive but actually it is an uploader as well as image processor. It has a very big list of functionality for resizing images, adding text to images, converting formats, etc. etc.
There is sample code which shows how to read an Image from server, modify it and finally send it directly to browser without having to create a temp file on server.
HTH

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