Mac App Store: https://itunes.apple.com/app/redacted/id984968384?mt=12&uo=6&at=1l3vmtU&ct=
Redacted makes it quick and easy to redact part of an image. Hide sensitive details of an image by simply clicking and dragging. You can redact an image in three different ways:
* Black bar
Quickly drag and drop an image into Redacted or simply paste and image to get going. When you're done, share it to Facebook, Twitter, and more with the Yosemite's new share menu or simply copy the image out of Redacted.