[UUMMUU]

Given a large Billboard (http://www.lamar.com/Products/Bulletins) size of 672 sq. ft. unless my math is wrong (could be) you're paying $100 for about .8 square inches. That would be visible from what? 5-6 feet away?

[lotsofmangos]

Is 9.67 square inches, your maths is out.

Which still only gives a square just over 3 inches on a side, so the kitties at the top of the board may get angry.

[UUMMUU]

Crap, sorry everyone for the crappy math. I did 672 * 12 instead of 672 * 12 * 12. Thanks to those who figured it out!

[l4yao]

672 sq. ft. is 96768 sq. in. If there are 10000 photos, each photo gets about 9.67 sq. in.