imagecreatefromjpeg and memory usage

springload

I am using imagecreatefromjpeg as part of a system that resizes images uploaded by a user. The problem is that if the user uploads an image which is too large then PHP dies with a fatal error:

Fatal error: Allowed memory size of 8388608 bytes exhausted

My question is - is there any way of computing how much memory a given image will require for imagecreatefromjpeg? That way I can check memory_get_usage() before attempting to call the function and can avoid calling the function if a given image requires too much memory (as compared to ini_get("memory_limit") ) and display a friendly error message rather than PHP's fatal error.

I can't see an obvious correlation between the filesize of a given jpeg and the memory used by imagecreatefromjpeg - my guess is it depends on how many colours there are etc.

Does anyone know a way of figuring this out and so avoiding the fatal error?

Cheers 🙂

schmeal

I was just wondering if you found at solution to the problem you were having with Fatal error: Allowed memory size of 8388608 bytes exhausted ? I've run into the same thing.

sandy4door

Same problem, I tried doing an imagecreatefromjpeg() on a 400Kb image and it used close to 8MB of memory (all of it) leaving none left for the imagecreatetruecolor().

The same procedure with a 50Kb image used about 2.3Mb for the imagecreatefromjpeg() and a further 1.25Mb for an imagecreatetruecolor().

Presumably the amount of memory used relates to the complexity of the image in the same way that two 50% quality jpegs of the same dimensions can have very different sizes.

Anyone got a rule of thumb for jpeg file size and memory usage?

Would ImageMagick use much less?

This is a pretty serious limitation on the GD libs for me as it means I can't build a muppet proof interface for my web site. Yes I can limit the file size my users are permitted to upload but if they have taken their photos straight off their digital cameras and don't know how to resize them they might well give up on trying to use my site all together!?!