A free program for Android, by Pictriev.

Cut+Mix Studio allows you to make an incredible collage, which you can then send to your friends after creating it.

This application will do the following: 

It will accurately cut out any object from a photograph by allowing the user to draw the boundary of the object simply. Natural carpeting is laid down in an automated fashion.

Combines a number of objects in any order, applying color changes and transformations to each one as it does so.

Allows the output to be saved as either a PNG file with a transparent background or as a JPEG file.

The resulting images are compatible with a variety of different photo editing applications.