1. Install GIMP
2. Download and install David's Batch Processor (DBP) http://members.ozemail.com.au/~hodsond/dbp.html
3. Make screenshots and put them in "screenshots\raw"
4. Using DBP, crop the images to 1007x661 and output PNGs to "screenshots"
5. Using DBP, resize the cropped images to 0.25 with a blur of 1.0 and put PNGs in "screenshots\thumbs"