Does anyone know how Remove Alpha Channel works and what Flatten Image exactly does (e.g. what operations it performs and in what sequence)? In particular, I'm trying to understand why they produce different results on a 1x1-px (single-layer) image with the following RGBA values for its only pixel: 78:69:128:254. Remove Alpha Channel produces a pixel with RGB values 79:70:128 while Flatten Image produces a pixel with RGB values 79:70:129. This was tested on GIMP 2.6.10 and 2.8.14. The background color specified in the toolbox was white (RGB values 255:255:255) in all tests.

**EDITS**

* added information about the background color