Finding correct resolutions / aspect ratios for PS1 games (easy way)

I'm using ePSe v.1.9.0., but I noticed that even with Stretching mode that has option Scale to window size, keep aspect ratio, it often only keeps 4:3 ratio even for games that aren't 4:3.
For instance, resolution of MediEvil is 512x240.

Anyway, it's actually pretty simple - start pSX emulator (because ePSXe, as far as I noticed, takes screenshots in resolutions that is set in emulator, not game's actual resolution), and just screenshot the gameplay part.
After that, just in some program for pictures calculate which higher resolution you want in that aspect ratio.

I personally use IrfanView; open picture --> click on Image --> choose Resize/Resample image --> Set new size: --> make sure Units are pixels, and Preserve aspect ratio (proportional) is activated.

Hope it helped, and sorry if I suggested something that was already known. :msn_confu