I Bought a Waveshare 7.3 inch 7-Color 800x480 Eink display and converting images was less than optimal, also, lightenting is easier Bought HERE [https://www.amazon.com/gp/product/B0C4TS1NMS/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1#customerReviews]
Using C# and GTKSharp
I also added the ability to "Lighten up" the picture as the display tends to be dim.
Tested on Linux
Go to Relases and download for Windows Linux or Mac