To do kits you need a image editing software (The default Paint that comes in with the Windows isn't enough). Personally, I think Photoshop is a bit difficult (and it's paid), so I use Paint.net (you can get it here: getpaint.net), it's not too hard to learn. Once you get the hang of it, you can make kits almost as good as those made with Photoshop.
There isn't an exact tutorial, it depends on the kit you want to do, I recommend you to get the hang of it. But changing colors and doing alts isn't too dificult, just do the following:
- Open the kit you want on paint.net
- Let's say you want to change color of the shorts. First, if it has any stripes or logos which need to change color, you have to change these colors first: I recommend you select them and move them to a new layer, so you can edit their color individually without worrying about messing up the other things of the kit. Don't forget that magic wand tool is very useful for removing backgrounds and such. Also, I recommend you search for a Anti Aliasing plugin and a Outline plugin (just google it, there are many plugins for paint.net which make it even more powerful
), they might come in handy.
- After changing the color of the details, choose the new color for the shorts (you can use the color picker tool if the color is already present anywhere on the kit). Use Filler tool on the shorts to fill it with the new color. Adjust hardness if needed.
- You can save it as a pdn file if you want to make changes later, but to use them in game you'll need to save it as a png or jpg file, which will merge all your layers
Then it should be ready.
One more thing: Yes, you can convert with this program, just use resize to change from 2048x2048 to 1024x1024. But you don't need to do this if you don't want: You can import 2048x2048 kits as
kits and the game does this automatically.
EDIT: some plugins I have on my paint.net are this: https://forums.getpaint.net/topic/7291-pyrochild-plugins-2017-12-04/
and this: https://forums.getpaint.net/topic/16643-dpys-plugin-pack-2014-05-04/