I have to develop a facebook app where user can select a photo from his photos and use as source image and place another image over it. The other image is a transparent png with a texture like dust. The user should be able to scale, rotate and move the source image so it fits in the other image.
Then the user should be able to save the final image to his facebook photos, so he can put it as cover or profile image. Finally tha app should write in user timeline and do the RSVP to an event (permissions for doing that should be given by the user when acepting the app).