Question

I’ve done some searching for this and I understand that it is not possible to recover from an exhausted memory fatal error. I have a script that runs imagecreatefromjpeg. I tried catching the exception, I tried running the function with @ and then checking the return value for null or false, I tried running it with ‘die()’. Nothing works. So I can’t ‘recover’ from it.

So is it possible to anticipate it before I get to it? Is it possible to check the uncompressed size of a jpeg and then die gracefully? I want to sent a message to my users along the lines of “The image $image is too large to process. You will need to create a thumbnail manually”.

My shared host won’t allow me to increase memory size beyond 64mb so that’s not an option. My code is as follows…

function createthumb($section,$filename,$constrain=100)
{
    $dir = "$section/thumbs_$constrain";
    if(file_exists($workingdir."$section/thumbs_$constrain/$filename")) return 1; 
    if(!file_exists($dir)) mkdir($dir);

    $src = imagecreatefromjpeg($workingdir."$section/$filename");
...

Answer 1

As a rule of thumb, you might use the size in pixels returned by getimagesize() :

list ($width, $height) = getimagesize($file);
$memory = $width * $height * 4; // 4 bytes per pixel

If this number is greater than a predefined limit (to be determined empirically, start with something like 32*1024*1024), then don’t load it with imagecreatefromjpeg().