http://www.beachmodel.com/webmasters/
Has 8 different size thumbs you can display for the POTD:
[150 X 200] [88 X 88] [90 X 120] [120 X 120] [150 X 150] [150 X 250] [240 X 360] [138 X 138]
Todays POTD in 240 x 360:
Come back tomorrow and this will auto update to a new one.
Cheers,
BV