Each puzzle is a grid with numerical clues; its solution is a small monochrome picture. The details at This site probably explain it far better than I ever could!
Because of the limitations of the Picture Logic game, they have been formatted down to 25 x 25 pixels and black and white only.
I have provided a copy of the collection to your site also, although, unfortunately only people who have registered copies of Picture Logic will find it useful. The file size is about 1K.
The Picture Logic File.