I developed a site under a dev domain, and when I migrated to the final domain I discovered loads of problems. All the photos we included on pages/posts as well as many links used the old dev domain instead of the new prod one. I even started fixing some of these by hand, but then got frustrated enough to try this plugin.
I have to admit, I was a little nervous to use this at first. But, I mustered up some courage and pressed the button. In less than 10 seconds, it fixed all the photos in 33 different galleries. So far everything is still intact and looks great.
I highly recommend this plugin!