PhotoChallenge Description:

The object of Photo Challenge is to uncover a partially hidden image as quickly as you can.
Photo Challenge consists of a grid of tiles (the puzzle window), each of which is in one of two states: solved or blocked. A solved tile displays a portion of the underlying image. A blocked tile hides a portion of the image. Clicking and holding down the left mouse button on a tile in the puzzle window will display a pattern on some of the tiles in the neighborhood of the tile that was chosen. When the mouse button is released, those tiles that were marked by the pattern will have their state flipped: blocked to solved, solved to blocked. The flip will occur only on the mouse button release. This allows you to investigate potential moves prior to making your next choice. Continue picking tiles until each tile in the puzzle window is in the solved state. Simple concept, difficult task?