Ambrosia has released Snapz Pro X 2.5.2 to fix an issue with accurately capturing the precise pixels of a selection and bring back support for several styles of image borders (which was excised in version 2.5). The update also improves the reliability of movie encoding, improves compatibility with both OS X 10.8 Mountain Lion and Retina displays, and adds Chinese and Russian localizations. ($69 new, free update, 15.8 MB, release notes)
Turn Off Filename Extension Warning
In Leopard, Apple fixed an annoying aspect of working with the Finder in Tiger. Previously, if you changed a file's extension, the Finder prompted for confirmation. But since no one has ever accidentally changed a filename extension, Apple thankfully added an option to turn that warning off in the Leopard Finder's preferences. Choose Finder > Preferences, and in the Advanced screen, deselect Show Warning Before Changing an Extension.