Here is a list of a just a few retouching services:
Add a subject from a photo.
Remove a subject from a photo.
Combine 2 or more photos.
Remove the background of a photo.
Colorize a black and white photo
Optimize a marginal quality photo so it can be enlarged.
Remove blemishes, Soften wrinkles and whiten teeth in portraits.
Remove time and date stamp.
Isolate one subject from a group to make a portrait suitable for display at a funeral.
Design custom cards and invitations.
Design and print trade show booths