Add image size to image src so that proper cropped image is served instead of original.

add-image-size-to-src.php

<?php
/**
 * Add image size to image src so that proper cropped image is served instead of original.
 * 
 * This is a very specific situation where the image tag has correct size attributes 
 * but, for some reason, the original source was used instead of cropped one. 
 * The code for serving image was in parent theme so editing that was not possible.
 */
$tags = new WP_HTML_Tag_Processor( $content );

while ( $tags->next_tag() ) {
	if ( 'IMG' === $tags->get_tag() && '360' === $tags->get_attribute( 'width' ) ) {
		$src = $tags->get_attribute( 'src' );
		// Get parts of src separated by '.' 
		$end = explode( '.', $src );
		// Get the last part - should be jpg, png, jpeg.
		$end = end( $end );
		// Get the image url up until last '.' 
		$url = substr( $src, 0, strrpos( $src, '.' ) );
		// Insert the size part in between. 
		$proper_url = $url . '-360x360.' . $end;
		// Set the proper crop URL as src attribute.
		$tags->set_attribute( 'src', $proper_url );
	}
}

return $tags->get_updated_html();