So I was trying to Flood Fill a small simple image. It was part of something complex, but the task was simple. Photo went into an apparently endless high CPU loop and eventually my machine blue screened. Much more complex operations had succeeded fine. No, I didn't have the wrong layer selected, and not finger trouble.
So I copied the little image to a separate tab and tried again, same result.
So I saved the little image to its own file. Restarted Photo and tried again, same result, except this time it did exit after several minutes but without making the required change.Camera Image.afphoto
Image is supposed to be pixel all created within Photo, but just to be sure I re-rasterised it - no idea what that actually does. However it fixed it and the Fill took about 3 nano-seconds. The attached file is the one that caused the problem. Try Flood Fill in another colour.
Windows 10 - fully up-to-date, Photo 2.1, Oodles of memory 32Gb, nothing much else running. CPU at peak from Task Manager 62%, memory usage 4Gb. This is a fast machine SSD with plenty of space.