Make sure you're using the latest version
I’m getting a number of crash reports (a couple in the last few hours) from people running older versions (usually RC1 or RC2). In this specific case (playing .img files) and others the bug has been fixed in RC3.
Unless you’re running into a specific problem with the latest version, it’s probably a good idea to upgrade. You can always check the about dialog if you’re not sure which version you have.
(And yes, the next release is dropping within the next few days, just finishing up on some testing…)