however, in general i find sites like this to help a TON with any jrock cosplay:
visual kei magazine scans galore! to find a specific group, GazettE for instance, just press Control+F buttons on your keyboard (or command+F for Mac user) and type in the name.
Scans are great to refer to because they're usually high quality so you can see lotsa details you wouldnt notice in a music video, plus theres usually at least one full body image that you can find of an outfit
hope that helps you and some other folks!