Now I didn't look through the tutorials but I am wondering if there was a tutorial to how to easily reskin something using gimp... for example:
also... how to increase the quality of a small picture when upsizing...
Voice of joy and sunshine
26th May 2003
I don't think there's any particularly easy way to do what you're talking about.
There's no real way to scale something up and add information to the image that wasn't already there. If you have a photographic negative, then you can blow the image up really big with an enlarger - but at the end of the day that's because photographic negatives are already very informationally dense for a given area of film. An image file on the other hand only contains as much information as the number of pixels in it, (subject to whatever encoding tricks it uses,) a 256*256 pixel image only contains 65,536 pixels worth of information whatever you do to it. When your computer enlarges the image, it looks at the pixels and guesses what would go around them based on their colors and positions. Which tends to make the image look blurry, blocky, or grainy - depending on how you do it.
In practice, if you're stepping up the quality significantly, you're best off taking the picture you have, resizing it in the normal way (i.e. go to image size and just enter the new dimensions you want), making a new layer on top of that, and then tracing the additions and corrections you want to make to it over the top - using the eyedropper from time to time to color match. Then you can add in whatever details you like and merge all the layers together when you're done.
But, as far as I'm aware, there's no real way to automate the task yet.
The problem here is that the image file is only half the equation. The 3d model will have, as part of it, a set of instructions that tell the computer where the different parts of the image file should be stuck onto the model. So if you just upscale the thing - altering the dimensions of the picture - it's entirely possible, depending on how the instructions go, that it will now stick the image onto the model in the wrong place.
It'd be like if I said, 'Everything from 1-150 pixels across and 1-150 pixels down you stick on this part of the model.' And, when you upsized the image to twice its size, suddenly everything that was in 1-150 pixels goes from 1-300 pixels. But my instructions still only tell the computer to stick 1-150 pixels on that side of the model.
Depending on how they've done it.
You could try upscaling the file just as a quick test, without doing anything else to it, and seeing whether that does mess up the way the image sticks to the file.
Again, your best bet is to use the original file as a guideline and draw any alterations you want to make onto that. Because you already know where on the model the parts of the file you're altering go.
Other than that though, it's just your skills as an artist. The guy you've shown seems to have just recolored a small part of the skin - which doesn't take much skill. Select the bits you want to alter the color of and apply the appropriate filter. The more skill you have as an artist the more dramatic the alterations you can make.
Oh, and in both cases, always keep a copy of the original file in a backup folder somewhere so you can replace the one that the game uses if you totally screw it up.