Photo downloads site plugin or theme suggestion

I’m looking for a theme or a plugin to achieve one task… I’m rebuilding various sites for one company and they have a media portal with images of their products etc.

I wan’t to be able to show them as a gallery and, when clicked, have a menu appear with the option to download in various resolutions.

Ideally, this would all happen from one screen.

Here’s their existing (hand-coded HTML) media portal which may give you an idea of what I’m after: