Though this tool is designed for discovering situations where an article contains an image but still has its talk page tagged as requiring one, it can be used successfully for any 'Main article has a .jpg image but talk page is in category Y type requests'. It was written after a request by en Wikipedia user PC78 and the SQL was written by toolserver admin flyingparchment and then edited by me. Technically speaking, this tool assumes only .jpg images are qualifying works and that any .jpg image (bar some limitations, see below) is indeed a qualifying work (even if its a 2x2 pixel template image, which are thankfully very rare).
Files containg 'stub', 'flag' or 'icon' are automatically assumed to not be qualifying works. The English Wikipedia also has its own blacklist, which you can view and add to. The scenario here would be that the tool lists works just because they have an image in their stub template, or something else like that. Add the name of that image to the watchlist.
Just specify a language and a talk page cat (both cAse SenSItive) and press 'Go!'. The PHP is designed to give you a usable URL that you can give to others.