This is a decently fast work in progress image scanner I created that so far uses a combination of run length, adaptive caching, rgb-space optimized unknown color searching, a low color space prescan to quickly determine the general rgb-space location for a more swift overall retrieval, and finally a more sophisticated scanning path to optimize the aforementioned features. Press space after your scan has completed to cycle forward to a debug scan with a cache access depth and time per line visualization, to an interactive scans per pixel visualization, and back to the image select screen. Thanks to @greenscripter for the rgb-ordering algorithm I stole out of laziness