Set custom sizes attribute on img in the post editor

Joe,

I don’t want to modify the default sizes attribute that is added to images.

I want to detect IF there is a sizes attribute already set on an img tag in the content. If there is, I want to use that. If there isn’t, I want to use the default.

I cannot do this by filtering wp_get_attachment_image_sizes.

I need to access to the $image string in wp_image_add_srcset_and_sizes.

I had to edit your plugin to get this to work.

In wp_image_add_srcset_and_sizes, I changed:

if ( $srcset ) {
		$sizes = wp_get_attachment_image_sizes( $size_array, $image_meta, $attachment_id, $src );
	}

to:

if ( $srcset ) {
		// Check if the sizes="" attribute was manually set on the image tag in the content.
		$sizes_regex = '/sizes="([^"]*)"/' ;
		$sizes_were_manually_set = preg_match( $sizes_regex, $image, $matches );
		// If the sizes="" attribute was manually set,
		if( $sizes_were_manually_set == 1 ) {
			// delete it from the $image string
			$image = preg_replace( $sizes_regex, '', $image );
			// and set $sizes equal to the capture group in the first match of sizes="" found in the $image string.
			$sizes = $matches[1];
		} else {
			$sizes = wp_get_attachment_image_sizes( $size_array, $image_meta, $attachment_id, $src );
		}
	}

It seems like setting a custom sizes attribute on each img tag in the content might be a pretty common use case. The user will know how large each image will appear on their website, and it seems kind to weird that a user cannot currently set sizes on a case to case basis.

Would you consider adding some kind of functionality to your plugin to support this(especially if this is going to be included in the wp core).

Thanks a 1,000,000,
-James

Awesome!

Thanks Joe