I recently watched first video of Noah Bradley's Art Camp in which he recommended doing some thumbnail value studies... I thought it was a great composition exercise so I did a few myself :) It was a ton of fun so I'll do color studies like these as well!
I'm sorry I can't provide with the names/authors of pieces -- I picked stuff out of my art folder and many of the names are as informative as "01.jpg" :/
Though... I hate it how the frame was plain grey on the computer I drew it on, and it's warm brownish gray on the one I'm using right now... Can't trust anything these days!