RoundPic is a free online service that gives the edges of your photos a makeover by rounding them off.
It works very simply: Browse to a photo on your hard drive and upload to the service. Alternatively paste in the URL of a photo that’s already online. Then click Round it! and wait a few seconds. RoundPic takes you to a screen where you can give your image a few more finishing touches like picking the corner(s) should be rounded, the type of rounding (on a scale from 1-12), the background color), and the dimensions and file-size of the newly rounded photo. Give the file a name and download it back to your desktop. Pros:
RoundPic is very fast and effective for quickly creating anti-aliased rounded edges on your photos.
Cons:
No batch operations.
The cluttered interface with the advertisements.
Overall, a nice tool to bookmark and re-visit when you have the urge to get rid of those sharp corners of a picture.