I have a question on the pico-8 palette. Sometimes I observed the behavior, that some colors changes on the pico-8 palette, when messing around with .png's.

For example, if I save screenshot directly from pico-8 and open it in an editor, that red, i.e. is sometimes displayed at R 251, G 0, B 61.

When I open the official pico-8 palette in one editor (in that case PikoPixel, OS-X), than red is again R 251, G 0, B 61. If I open the same file in another editor (Pyxel Edit, OS-X), then red becomes R 255, G 0, B 77. If I import the same image as palette in Pyxel Edit, red again becomes R 251, G 0, B 61.

Is someone able to explain this behavior? Or had similar observations and can help by adding use-cases?

When comparing colors from different sources (in your case, screenshot-image vs. palette-file), make sure both colors are represented using the same color profile; If the profiles don't match, two visually-identical colors can have different RGB values.

There's some more info on color profiles in this stackoverflow answer:
http://stackoverflow.com/questions/30050879/color-picker-on-mac-os-x-selects-wrong-colors

Oh, thanks a lot. I'll look that up later.

PikoPixel! Meanwhile literally everyone seems to be present in the pico-8 community...! ;)