Editing photos to get the most out of them can be brutal if you don't have the right tools. Depending on what you want to do, those tools can be quite pricey.
There are cheaper alternatives, iOS photo-editing app, is now available on OS X and it isn't terribly expensive.
To edit a photo, you can either drag and drop one onto the apps icon in your dock, or you can go to File > Open.
Once you have imported the photo, you will see two columns of thumbnails for enhancements or adjustments you can perform on each photo. Clicking on a thumbnail will bring up a specific set of settings for that effect.
Clicking on the respective adjustment will apply the special effect. You can then adjust the applied effect using the global adjust sliders below the thumbnails.
You can even narrow down or limit adjustments to a specific area of the picture for some adjustments by adding a control point, although this option isn't available on all of the adjustments.
After you are happy with an adjustment, you can click on Apply or Cancel in the lower left-hand corner. Apply will, of course, apply the adjustment to the photo. Clicking on Cancel will leave the image as it were before you added the particular effect.
You can also revert back to the original photo at any time by clicking on Revert located in the bottom-left corner of Snapseed when viewing the photo with no adjustments selected. No matter how many effects were applied, clicking on Revert will take the photo back to its original state.
Sharing photos with Snapseed is a breeze. Sharing buttons are built into the app, unless you are in full-screen mode, you will need to look for the option to share in the menu bar. Clicking on the desired share method will allow you to print, send to Facebook/Flickr/Mail or save the photo.
You can purchase Snapseed in the Mac App Store for $19.99. It currently is compatible with OS X 10.6.6 and above. The reviews in the Mac App Store indicate issues when trying to get the app to run on a Core Duo, so act with caution if you are sporting an older Mac.