Free
Picasa
Google’s old answer to iPhoto
Cool App for Shutter Bugs
Backup to Picasa for iPhoto is a special app that captures all photos that have been taken using iPhoto and uploads them to Picasa. The app runs in the background and uploads instantly as soon as photos are taken. People who regularly upload photos to Picasa are likely to find that Backup to Picasa for iPhoto saves them a lot of time and trouble, although it should be noted that the app is not compatible with all versions of iPhoto.
Download Adobe Photoshop for Mac : A powerful graphics and photo editor
Unleash your creativity with Adobe Photoshop Lightroom for Mac
Comprehensive Update for Adobe Photoshop on Mac
Central distribution platform
Versatile image processing for scientific and creative use
Free
Google’s old answer to iPhoto
Paid
Apple's software for viewing and managing your photos
Trial version
Powerful Instagram style photo editor
Free
Free Photography App for Mac Users
Free
Free Photography Software for Mac Users
Free
Effortless Image Resizing with iResize
Organize Your Photos with iPhoto Library Manager
Free Photography Software for Mac Users
Parametric patterns and illustrations
A GUI for mencoder/mplayer
Carousel: A Trial Photography App for Mac
Flux: A Trial Photography App for Mac
Enhance Your Photos with ColorizeYourPhotos
Quickly view the meta data of your images