[support] Restting image file type

Hello, I did something on a nearly to be deployed production site, and now i can't access the admin/structure/file-types. I have added some extra fields to the image file type and now i would like to remove them as this caused me extra trouble and my approach didn't work with the "custom exif" module, which i have uninstalled. Can someone tell me which tables should i alter to get back the file type image whitout the extra fields i have added. TIA