@include /^https:\/\/(www\.)?google\.(com(\.[a-zA-Z]{2})?|co\.[a-zA-Z]{2})\/search\?([^&=#]+=[^&=#]+&?)*tbm=isch/

@include /^https?:\/\/(www\.)?google\.(com(\.[a-z]{2})?|co\.[a-z]{2})\/search\?([^&=#]+=[^&=#]+&?)*tbm=isch/
thinking about it now you wouldn't need uppercase letters, all modern browsers rewrites it anyways
also could make https optional it's your decision to make

@include /^https?://(www.)?google.(com(.[a-z]{2})?|co.[a-z]{2})/search?([^&=#]+=[^&=#]*&?)*tbm=isch/

wait, you don't actually need to supply values for search params

@include /^https?:\/\/(www\.)?google\.(com(\.[a-z]{2})?|co\.[a-z]{2})\/search\?([^&=#]+=[^&=#]*&?)*tbm=isch/
how do i edit posts

@include /^https?:\/\/(www\.)?google\.(com(\.[a-z]{2})?|co\.[a-z]{2})\/search\?(([^&=#]+(=[^&=#]*)?)?&?)*tbm=isch/

this should be good

I understand your feedback.
I will update to match with google.tld to match with any top level domain.

Updated with the latest version.
Tested with google.com, google.de, google.co.cr image sites. Let me know if any specific domain is not matched.