I've had Acdsee (2) forever. I got a newer version (4) with some hardware I bought recently. Well, the new version wasn't was partially what I wanted, but it had some problems - not sure (wouldn't associate gifs - beats me)
Anyway, it got me looking for alternatives. What's out there besides Acdsee these days?
Graphic Converter is my swiss army image opening app of choice, but the few times I've tried to edit something in it, I quickly realized why it's not a commercial app. Not stupendously intuitive or user-friendly, but it does open almost anything.