Blogger Issue?

In multiple browsers and on multiple computers I'm finding that if I click on a picture I've posted rather than simply having the larger version open in a browser window I'm being presented with the option of opening it with my default image viewer or downloading the picture.
Anyone else finding that to be the case?
If so, it's not the result of anything I've done - I've just been posting the the same way I always have, so it might be some kind of issue with Blogger.