We don't feature promotional videos by the band or their representatives which were made just to inform the fans that a new album is on the horizon or where to buy the new album!
There's a lot of custom-made videos floating around, usually with anime footage. Learn to distinguish between them.
Check the media section of the bands whether they have videos. If yes, add those. You can also try to find information on fan sites. Most of the time you won't find many videos on the band's site. Check out YouTube.com then, enter the band's name and find the official videos.
Google Video and Youtube normally have good enough quality to take a proper screenshot (PrtScn button on your keyboard). If you can download the video somewhere, follow this short guide: http://www.videohelp.com/faq#screenshot.
Please take a screenshot that is representative for the video. Full view of the band isn't representative, every music video has that. Best is if you take a shot of a scene, which is crucial for the plot of the video.
This is the year the video was released, not the album! If there's no way to find out - oh well, put the album year here...
The toughest part. If you have trouble finding the director, browse through the archives of Blabbermouth or Brave Words and/or google interviews with the bands from that period. ("band name" "song name" video interview) as search query should do the trick.