HughJanus said:create a square/recatangle selection with the marquee tool, then holding the shift button (a small + symbol will appear next the the cursor) change the marquee tool to a circular selection, draw a circle....this will add a circle to your current square selection.
you may find it easier to use the guides to ensure all the corners are the same
if you want i can make a quick movie to show you if ya want?
edited: got it the wrong way round...now amended
decksnap said:That does not sound like a very efficient way to do this. Under the line tool there is a rounded-corner rectangle tool. Use this to generate a shape or path with which you can then either mask your image to the shape or generate a selection from the path and cut out your image. This tool has a setting on the top to allow you to change your corner radius.