Comment # 4 on bug 107482 from Michel Dänzer

(In reply to Sebastian Luncan from comment #3)
> For the first attached imaged I've applied gamma with Gimp.

How exactly did you do that?

Anyway, I don't think there's a bug here. Gamma doesn't affect all colour
values the same way (in particular, 0 and the maximum value are preserved for
each colour component). The "colourful" pixels occur because the original
pixels have 0 or a very small value in some components but larger values in
others, which are affected differently by gamma.