I just found two very simple but helpful things! I’m so excited I had to share.

First, a nice list of specs for various popular video upload sites:

http://www.videomaker.com/article/14570/?utm_source=enews&utm_medium=email&utm_content=tip_enews_2010_02_1&utm_campaign=traffic

and second, a dummy image generator:

http://dummyimage.com/

(All you have to do is modify the URL to generate placeholder images of any size: http://dummyimage.com/390×321)

Both of these sites would have come in handy a zillion times over the last few years. Give them a try!