There was a time when photographs were primarly delivered by means of chemically treated paper. Yes, that sounds like crazy talk now. But, it is true. People would sometimes take these chemically treated papers with images on them and assemble them on a larger piece of paper or poster board in arrangements they called collages. You can try your hand at collage making without bother with paper using a new free iPhone app:
The app lets you select multiple photos to include in a collage. The, it has you select a shape in which to places your photos. These shapes in a heart, circle and words (text character shapes). You can use up to 100 different photos to create these shape collages. Once completed, the photo shape collage can be shared using Facebook, Twitter or email.
Shape Collage (iTunes App Store)