Image Capture with IRfanView- by gwar3k1

Open IrfanView and go to "Options > Capture Screenshot"

Make sure "Foreground window - Client area" is selected and "Include mouse cursor" is deselected.

Choose a key sequence that won't interfere with your emulator's controls but is easy to use. Personally, I have Ctrl+` which is close to my action buttons but doesn't get accidentally pressed.

Select "Save captured image as file" and select a "Destination directory" and "Save as" JPG - JPEG Format.
Click "Options" and set the "Save Quality" to 80 or 100 based on what you think is better for you.

Click "Start" and irfanview will minimise. Your hotkey (Ctrl+` for me) will take a screenshot of the program you have last clicked on without it's border. Make sure you click your emulator before starting to take screenshots.

Batch Processing in IRfanView - Crop / Resize

Open IrfanView and go to "File > Batch Conversion / Rename"

Click "Add" which is one of the buttons on the left, then select all the pictures you want to be resized. You can also drag and drop.

In the "Work as:" group, make sure "Batch Conversion" is selected.
Also make sure that "Use Advanced Options" is selected and click "Set advanced options"

Here, you can crop and/or resize your images. State the dimensions that you want the final images to be.

For games where the art is pixel style (>= 16-bit era) deselect "Use Resample Function", but if your game is smooth graphics, make sure it is selected.

Click "OK"

Set the "Output Format" to JPG - JPEG Format and click "Options"
If your images have been compressed at an unknown ratio, set "Save Quality" to 100 "Best", if it's a raw image, set it to 80.

Click "OK"

Select an "Output directory" in a different folder to the original images. When you are ready, click "Start" and your images will be resized in the chosen folder.