Find out the php file type - php

Please tell me how can I check the file for its real type?
When executing the imagecreatefrompng() function, it displays an error: is not a valid PNG file.
mime_content_type() says image/png file.
This file...
<?php
$file_name = $_SERVER['DOCUMENT_ROOT']."/walko.png";
$new_file_name = $_SERVER['DOCUMENT_ROOT']."/walko.webp";
$img = imagecreatefrompng($file_name);
imagepalettetotruecolor($img);
imagealphablending($img, true);
imagesavealpha($img, true);
imagewebp($img, $new_file_name);
imagedestroy($img);
?>
PHP 7.4.9

It seems that your png file is too big, and PHP is unable to allocate enough memory.
When you run:
$img=imagecreatefromstring(file_get_contents($new_file_name));
You get more accurate error description:
Warning: imagecreatefromstring(): gd-png error: cannot allocate image data
Then it seems that gd is unable to allocate memory and as it's said in libgd FAQ:
Why does gd cause my PHP script to run out of memory?
Most often, the problem is that the memory_limit parameter in php.ini is set to something very conservative, like 8M (eight megabytes). Increase that setting and restart the web server. Of course, opening truly huge images can cause real memory problems, if several are open at once. 8,000 pixels times 8,000 pixels times four bytes for truecolor equals a walloping 256 megabytes.
That seems the cause of your problem.
Also there's a related question here:
gd-png cannot allocate image data
So if you recude png size it should work also you can increase PHP memory limit memory_limit in PHP ini. In my case your initial script worked because I have a high value.

Related

PHP Compress Image

I am trying to compress an uploaded image using imagefromjpeg but I get this error:
Fatal error: Allowed memory size of 67108864 bytes exhausted (tried to allocate 24000 bytes)
The image is only 13215317 bytes big - why do I keep getting this error? I can not ramp up the memory for the server myself - so is there a way to compress without loading the entire image at once?
$image = imagecreatefromjpeg('../../uploads/DSC_0230.jpg');
imagejpeg($image, '../../uploads/DSC_0230.jpg.new', 0.8);
imagedestroy($image);
Loading an image into PHP this way will first uncompress the JPEG into raw pixel data in memory, and then generate the new version. It will therefore take memory equivalent to two raw bitmaps at the image's resolution, plus the other overhead of PHP and your script.
Since all you're doing is recompressing the image with different options, you will probably have better performance with a tool built for just that job, such as jpegtran or jpegstrip, or a general image manipulation tool like ImageMagick.
You could then call those from your PHP script using shell_exec - being very careful that you have validated the filename so that someone can't use it to run arbitrary commands.
Issue:
Your hosting provider offers you service with only a 64Mb memory limit.
Your image upload has a larger than 64Mb memory usage as uncompressed raw pixel data.
Solutions:
1) Increase your memory limit in PHP.ini file, typically with :
memory_limit = 128M
2) Increase your memory limit on your page only, editing the php.ini only for that page execution :
ini_set('memory_limit','128M');
3) Limit the size of the original file upload.
there are a few ways to do this, so please read the PHP manual as well as reaseach some useful posts found via Google Searching.
4) You can also try and resize the image before uploading.
From your statement that you cant edit the PHP.ini with ini_set then it looks like you should use option 4 and 3.
Also, your current code is incorrect.
imagejpeg($image, '../../uploads/DSC_0230.jpg.new', 0.8);
The compression value should be an integer between 0 and 100. to correctly set the saved JPEG to a proper compression level:
imagejpeg($image, '../../uploads/DSC_0230.jpg.new', 80);
This will save the image to a value of 80 compression(the value it looks like you're attempting with 0.8).

PHP out of memory, last chance function call? [duplicate]

I get this error when users are uploading images on my site.
error msg is "PHP Fatal error: Out of memory (allocated 80740352) (tried to allocate 12352 bytes) in /home......."
How can I fix this using php.ini?
Here is my current upload php.ini settings
upload_max_filesize = 2000M ;
post_max_size = 2000M
max_file_uploads = 8
Any ideas what else I need to add to solve this error?
The optimal memory_limit value depends on what you are doing with the uploaded files. Do you read the files into memory using file_get_contents or the GD library? In that case, increase memory_limit to at least the same as upload_max_filesize, preferably more.
If you are using GD, keep in mind that GD holds the entire image uncompressed in memory. This means that it takes memory in the range of width * height * bit-depth, e.g., 1024*768*32 = 25 165 824 bits = 3 MB for a screenshot, or as much as 55 MB for a 14 megapixel image.
Some operations may need to create a copy of the image, so consider setting memory_limit to the double of what you need to keep the image in memory. Also make sure to not load all images into memory at once if you don't have to. You can free the memory used by GD by calling imagedestroy on the handle when you are done working with the image.
set_time_limit(0);
ini_set('memory_limit', '20000M');
To the top of your script. Change the 20000M accordingly.
Increase your memory limit from php.ini
memory_limit = ...
Uploaded files are saved in memory, so you should also to increase memory at least the same size of the expected file.
memory_limit = 2000M // better 2200M or above, just in case.

php image copy/crop/resize memory limits [duplicate]

Fatal error: Allowed memory size of 33554432 bytes exhausted (tried to allocate 4912 bytes) in /var/www/development/example/system/libraries/Image.php on line 130.
The JPEG image in question does not have a particularly large file size (741 KB). We've used this same code to rebuild larger images. However, the image does have unusually large dimensions (4912px x 3264px). Would this have an effect?
What determines memory usage when PHP is rebuilding an image? Is it just the file size? The dimensions? The colour density? The file type?
The line on which it broke was
$f1 = 'imagecreatefrom' . $tag;
$src = $f1($file);
I think that's enough context. It didn't get as far as trying to rebuild the image. Loading it into memory was enough to break it.
As riky said, set the memory limit higher if you can. Also realize that the dimensions are more important than the file size (as the file size is for a compressed image). When you open an image in GD, every pixel gets 3-4 bytes allocated to it, RGB and possibly A. Thus, your 4912px x 3264px image needs to use 48,098,304 to 64,131,072 bytes of memory, plus there is overhead and any other memory your script is using.
Increase your memory buffer size
php_value memory_limit 64M in your .htacess
or ini_set('memory_limit','64M'); in your php file
It depends your implimentation. last time when I was working on csv file with more then 500000 records, I got the same message. Later I introduce classes and try to close the open objects. it reduces it memeory consumption. if you are opening an image and editing it. it means it is loading in a memory. in that case size really matter. if you are operating multiple images. I will record to one per image and then close that image. In my experience when I was working on pdf artwork files to check the crop marks. I was having the same error.
//you can set the memory limits values
// in htaccess
php_value memory_limit 64M
//or in you using following in php
ini_set('memory_limit', '128M');
//or update it in your php.ini file
but if you optimize your code. and use object oriented aproach then you memory consumption will be very less. because in that every object has its own scope and out of that scope it is destroyed.
The size of the used memory depends on the dimension and the color bit depth.
I also ran in to that problem a few years ago, while building a portfolio-website for photographers. The only way to properly solve this is to switch your image library from GD to imagick. Imagick consumes far less memory, and is not tied to the PHP memory limit.
I have to say that the images the photographers uploaded were up to 30MP. And setting the memory limit to over 1024MB makes no sense in my eyes.

PHP rebuilding images: memory usage

Fatal error: Allowed memory size of 33554432 bytes exhausted (tried to allocate 4912 bytes) in /var/www/development/example/system/libraries/Image.php on line 130.
The JPEG image in question does not have a particularly large file size (741 KB). We've used this same code to rebuild larger images. However, the image does have unusually large dimensions (4912px x 3264px). Would this have an effect?
What determines memory usage when PHP is rebuilding an image? Is it just the file size? The dimensions? The colour density? The file type?
The line on which it broke was
$f1 = 'imagecreatefrom' . $tag;
$src = $f1($file);
I think that's enough context. It didn't get as far as trying to rebuild the image. Loading it into memory was enough to break it.
As riky said, set the memory limit higher if you can. Also realize that the dimensions are more important than the file size (as the file size is for a compressed image). When you open an image in GD, every pixel gets 3-4 bytes allocated to it, RGB and possibly A. Thus, your 4912px x 3264px image needs to use 48,098,304 to 64,131,072 bytes of memory, plus there is overhead and any other memory your script is using.
Increase your memory buffer size
php_value memory_limit 64M in your .htacess
or ini_set('memory_limit','64M'); in your php file
It depends your implimentation. last time when I was working on csv file with more then 500000 records, I got the same message. Later I introduce classes and try to close the open objects. it reduces it memeory consumption. if you are opening an image and editing it. it means it is loading in a memory. in that case size really matter. if you are operating multiple images. I will record to one per image and then close that image. In my experience when I was working on pdf artwork files to check the crop marks. I was having the same error.
//you can set the memory limits values
// in htaccess
php_value memory_limit 64M
//or in you using following in php
ini_set('memory_limit', '128M');
//or update it in your php.ini file
but if you optimize your code. and use object oriented aproach then you memory consumption will be very less. because in that every object has its own scope and out of that scope it is destroyed.
The size of the used memory depends on the dimension and the color bit depth.
I also ran in to that problem a few years ago, while building a portfolio-website for photographers. The only way to properly solve this is to switch your image library from GD to imagick. Imagick consumes far less memory, and is not tied to the PHP memory limit.
I have to say that the images the photographers uploaded were up to 30MP. And setting the memory limit to over 1024MB makes no sense in my eyes.

Uploading images with PHP and hitting the script memory limit

I am trying to upload a JPG image using a PHP script, but the image is keeps causing my script to time out and die giving this error:
Fatal error: Allowed memory size of 33554432 bytes exhausted (tried to allocate
2136 bytes) in image.php on line 38
How can I prevent the upload from taking place if the image is too big, or have this error fail gracefully?
The actual problem is not with the initial file size but with the dimensions of the image itself (heightwidthcolorDepth), since you don't have access to this information before the file has been uploaded for security reasons, you should probably use an uploader written in Flash, Java or Silverlight since they DO have access to this information beforehand.
After the upload you can check if the image will exceed your memory limit by calculating the dimensions of the (uncompressed) image by using getimagesize and using the returned width, height and bit depth.
Best of luck.
http://php.net/manual/en/features.file-upload.common-pitfalls.php says:
If a memory limit is enabled, a larger memory_limit may be needed. Make sure you set memory_limit large enough.
You can limit image size or any other file upload size on couple of ways,
via php.ini, upload_max_filesize = 10M
via invisible tag such as this(10k):
<input type="hidden" name="MAX_FILE_SIZE" value="10000" />
I Would not recommend increase memory limit if you don't know what kind of implications it can have on your server configuration.
Just set the memory limit higher for that particular script only by using ini_set.
At the beginning of your image processing script:
ini_set('memory_limit', '64M');
This error is generally caused not by image file size, but rather image resolution. So you can run some check for the size of the image. Run some tests to see what's acceptable under your current memory limit, and if the resolution is higher then kill the process and return an error to the user.
$size=filesize($_FILES['image']['tmp_name']);
will give you the size of the file in the global $_FILES array. After this, just compare $size to the maximum size you want.
Check out thie filesize() api: http://php.net/manual/en/function.filesize.php
Is this happening with all upload attempts regardless of file size? I have only experienced this sort of problem when there has been a scripting error - usually a loop that is out of control.

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