Media: Only mark an image as requiring conversion if the output format differs from the input format.

Follow up to [59317] and [59346].

Props adamsilverstein, peterwilsoncc.
See #62305.


git-svn-id: https://develop.svn.wordpress.org/trunk@59366 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/includes/image.php

@@ -301,7 +301,11 @@ function wp_create_image_subsizes( $file, $attachment_id ) {
 			// The image may need to be converted regardless of its dimensions.
 			$output_format = wp_get_image_editor_output_format( $file, $imagesize['mime'] );
 
-			if ( is_array( $output_format ) && array_key_exists( $imagesize['mime'], $output_format ) ) {
+			if (
+				is_array( $output_format ) &&
+				array_key_exists( $imagesize['mime'], $output_format ) &&
+				$output_format[ $imagesize['mime'] ] !== $imagesize['mime']
+			) {
 				$convert = true;
 			}
 		}