Disable resizing of gif when uploaded

Question

Animated gifs are getting more popular on the web (again) and currently there is no good tool for resizing animated gifs.

So I want to disable resizing/generation of image sizes for the gif mimetype and just save the original gif.

Someone that can help me out with this? Which filter to use will be a good start.

Answer 1

image_make_intermediate_size was not the hook I was looking for, but intermediate_image_sizes_advanced.

Here is a working code:

function disable_upload_sizes( $sizes, $metadata ) {

    // Get filetype data.
    $filetype = wp_check_filetype($metadata['file']);

    // Check if is gif. 
    if($filetype['type'] == 'image/gif') {
        // Unset sizes if file is gif.
        $sizes = array();
    }

    // Return sizes you want to create from image (None if image is gif.)
    return $sizes;
}   
add_filter('intermediate_image_sizes_advanced', 'disable_upload_sizes', 10, 2); 

Answer 2

currently there is no good tool for resizing animated gifs

Resizing of animated gifs is supported by ImageMagick, which happens to be the default image library of WordPress. The only thing is WP doesn't support this filter in its default API to ImageMagick.

Fortunately, it is possible to intercept image_make_intermediate_size, the hook that produces the resized images. Here you could intercept gifs and have them handled in a different way. Perhaps you could take inspiration from this image sharpening plugin to see how to apply ImageMagick methods to your images.