Just created this custom screensaver creator for the Touch and Paperwhite 2 (and any other kindle that can use 758 x 1024 or 600 x 800 screensavers). Click the link on the left to toggle between paperwhite and touch.
Select a large jpg or png, and it lets you zoom and crop and convert to black and white, then right-click to save as a black and white PNG.
Everything takes place on the client-side so nothing is uploaded.
Please let me know if you have any feedback or questions.
https://crowned.github.io/kindlesaver/
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