Complex sentence: As an incentive to increase coverage, participants are awarded a point each time they contribute a first geograph to a grid square, but there is no limit to the number of photos per square and some squares have over 100.
Split into simpler sentences: As an incentive to increase coverage, participants are awarded a point each time they contribute the first photograph classified as a "geograph" to a grid square. There is, however, no limit to the number of images per square, and some squares have over 100.