Yeah, I used ZSNES to capture the frames of sprites for use in my avatars

And a fairly old version too, since this was quite a long time ago I did that. If you hit F1 while it's emulating the game, it should pause and give you a list of options to choose from, including saving a screenshot to BMP or PNG image files, and a useful Advance 1 Frame option, good if you want to capture a sequence of frames
epsxe is the best for PS1 emulation, but it's also not easy to configure if you want it working great