Oh, just another tip (which you may actually know already, but meh...). If you're using DesMuMe, you can take screenshots at the press of a single button! All you have to do is go to:
- Config → Hotkey Config
Now, from the dropdown menu, select Tools and in the Quick Screenshot field put the key with which you want to take your screenshots (usually F12). They'll be automatically saved to the directory specified in Config → Path Settings. However, their resolutions will be fixed at only 240px I believe (can't remember).
When I take mine, I instead use PrntScrn, paste them in MSPaint and crop them with an online photo editor.