The tools you mentioned can be set to use "Interpolation: None". That way they won't create any mixed colors. But even when you switch off interpolation, automatic transformation always look strange in pixel art, because these tools can't detect features like one pixel wide lines or dither patterns and preserver them.pateame wrote:[+] GIMP; I can sketch and do animations faster using layers, but if I apply any effect/rotation/resize, my color pallete is filled with colors that did not want to add and everything becomes a "pillow" to fix later (twice work to do).
You can also use GIMP in indexed color mode (picture->mode->indexed). That way you can guarantee that you won't get any unwanted colors in your image. But this has the disadvantage that deliberately adding new colors becomes more difficult and a lot of features are completely unavailable.
I always work in RGB mode and just avoid the tools which create mixed colors.