Sell photos on your site through Fotomoto.
Fotomoto is a service that allows you to sell prints of your photos through your web site. While Fotomoto does provide an official module ( http://codex.galleryproject.org/Gallery3:Modules:fotomoto ) I find that it lacks certain features that I feel are important (like the ability to have their site automatically retrieve high resolution photos for printing) and I have thus made my own module.
This module may be downloaded from the Gallery forums here.
This module installs like any other module -- extract the fotomotorw folder from the attached .zip file and upload it to the gallery/modules directory on your web server. Afterwards log in as an admin and activate it from the modules page (it shows up as "Fotomoto (rWatcher)" to distinguish it from the official module).
Once it's activated, select Admin -> Settings -> Fotomoto to configure the module. You will need to sign up for an account on Fotomoto's web site and enter the site key they give you onto the module's configuration page. The module will then display a few links underneath photos for buying prints and stuff. You can control which links are displayed from the module's configuration page.
If you want to have Fotomoto automatically retrieve high resolution photos when orders are placed, you will need to configure this on their web site. Instructions for doing so are at the bottom of the module's configuration page.