Pattern used for image urls: in attributes: https://regexr.com/46jat in css: https://regexr.com/46jcg In case reqexr.com should be down, here are the content: # in attributes *pattern:* (?<=(?:<(img|source|input|iframe)[^>]*\s+(src|srcset|data-[^=]*)\s*=\s*[\"\']?))(?:[^\"\'>]+)(\.png|\.jp[e]?g)(\s\d+w)?(?=\/?[\"\'\s\>]) *text:* Notice: The pattern is meant for PHP and contains syntax which only works in some browsers. It works in Chrome. Not in Firefox. The following should produce matches: In srcset, the whole attribute must be matched Common lazy load attributes are matched: The following should NOT produce matches: ----------------------------------------- Ignore URLs with query string: src="http://example.com/header.jpeg"