Picture Pieces is a photo mosaic creator. Choose a picture from your photo library and Picture Pieces will create a mosaic of that photo using all of the other photos in your library! Import photos using the camera, your photo album, or connect to Picasa and use your existing albums. You can save, open, and share the high resolution mosaics you create with your friends and family, or send them to yourself for later printing and post editing! Use the pinch to zoom capabilities of your iPhone, iPod touch, and iPad to see all the details of your creation!
The main screen shot that is seen on iTunes is a zoomed in view of the icon mosaic!
For importing large amounts of images use Picasa. There is currently not a select all option via the iPhone image picker...