Apple's ColorSync Utility is built in to OS X. ColorSync profiles are used in image-rendering devices so colors will match across different devices. For instance, if you have two monitors attached to your system that are of different makes or models, then it is likely their pixel response ranges are slightly different. As a result, reds may be more vivid on one monitor than on another one, or the blues may be deeper. These variations can be allowed for by creating a color profile for each device, so when image data is passed between them they will display it accurately.
In addition to having color profiles for devices, you can have a color profile embedded in an image. This enables the image to preserve its colors as displayed on one device when transferred to another device. In addition to embedding a profile for dynamic translation, you can adjust the raw image content by matching it to a profile, which has a similar effect without tagging the image with a new profile.
While various photo-editing software packages can do this, including Apple's Preview application (though Preview only supports assigning profiles and no other profile-based manipulations), using ColorSync Utility can be a quick way to do this for individual images, especially if all you wish to do is change color profile settings. Just open the image with ColorSync Utility by dragging the image to the utility's icon (either in the Dock or in the Finder) or by using the utility's standard Open command in the File menu.
After the image is opened, you can use the ColorSync profile tools that are available at the bottom of the window to either apply a new profile or adjust the image based on a selected profile.
In addition to applying ColorSync profiles, ColorSync Utility has some rudimentary options for editing pictures, including resizing, and adjusting exposure, black and white points, gamma, contrast, sharpness, and other details. These options are available in the toolbar.