Solar_3200x1200_* partly transparent column of pixels

[Charlie Brej]

Another little thing:
For a technical reason[1] the last image, in the array of sizes in the 
background transition xml, is the one chosen for the thumbnail. In solar, this 
currently is the dual screen which very few people have and in most single 
screen setups the thumbnail looks quite distended. Would it be possible to 
reorder the size elements in the xml so either the 4:3 or maybe the 16:10 
appears last and will be chosen for the thumbnail?

[1] gnome-bg uses prepend reather than append in list functions presumebly for 
performance reasons