content: Edited to be less of a jumbled mess... You want to use the Color Replacement tool (obviously). The settings here are only guidelines. Also, I did this in Photoshop, but it should apply to GIMP as well.   Mode: Hue - You might think you would want to use Color mode, but that's too severe for a natural result. Hue leaves the saturation, luminosity and color alone, which keeps the natural variations that occur in every face. So the whiter a jew is, the lighter the blue. For niggerkikes, the blue is darker, as is their skin.   Sampling: Continuous - This will constantly take samples of the area under the center of your brush as you paint, keeping you from having to constantly retouch areas as the hues vary subtly across the image due to natural variances or lighting.   Limits: Find Edges - This one is the real key. It constantly looks for the border between areas of different color, and will ignore areas where the brush crosses a certain threshold, defined by the next value. This makes things much, much easier if you're using a mouse instead of a tablet.   Tolerance: Adjust as Necessary - I usually start with about 30%, which is good enough for most large areas with good definition, and also keeps from painting over facial features too much. If you get into areas like the scalp or hairline, you can decrease the tolerance (along with the size of your brush) so that it requires much less of a change to cause a resample.   As for the editing itself, just go slow and take your time. Be sure to adjust the tolerance and brush size to suit the area you're working in. When you get close to an edge, you can rough it in, then go back with a smaller brush to get those little fringes of color on the edges that usually happen (in this case, the microphone cable had a couple on either side). One thing to pay special attention to is things like reflections on jewelry. You'll want to zoom in and touch those up as well for the best effect. I could have done better on the watch, but you can see what I'm talking about where the arm is reflected on the edge of the band. Another thing is to look for lighting that's been (for lack of a better term) back-scattered onto clothing, etc. If you look really closely at the inside of the sleeve, you'll see what I mean. There was a reddish tinge there due to the light reflecting off of the arm and hitting the white fabric of the sleeve, so that got touched up with the Color Replacement tool as well. Finally, make sure you leave the hair, eyes, lips, teeth, blemishes, and any facial hair alone (if you can get any visible patches of skin that might show behind facial hair, more power too you). That prevents it from looking like you just slapped a translucent blue filter over the image. The fact that it gives them a slightly clown-ish look due to the contrast of red and blue just highlights the fact we live in clown world even more. Once you're used to how it all works together, it shouldn't take more than 5 minutes or so to do an image properly.