How to extract frames of an animated GIF with PHP

Well, I don't really recommend doing it this way, but here's an option. Animated gifs are actually just a number of gifs concatenated together by a separator, "\x00\x21\xF9\x04". Knowing that, you simply pull the image into PHP as a string, run an explode, and loop through the array running your transformation. The code could look something like this.

$image_string = file_get_contents($image_path);

$images = explode("\x00\x21\xF9\x04", $image_string);

foreach( $images as $image ) {
  // apply transformation
}

$new_gif = implode("\x00\x21\xF9\x04", $images);

I'm not 100% sure of the specifics of re-concatenating, the image, but here's the wikipedia page regarding the file format of animated GIFs.

I spent my day creating a class based on this one to achieve what I wanted using only PHP!

You can find it here: https://github.com/Sybio/GifFrameExtractor

Thanks for your answers!