I tend to use Photoshop, but for my engineering course I do want to use something as simple as MS Paint.
I literally need to do this:
But when I do it, the whole image is dithered. Which completely kills my program. If I filled my shape with a solid color, it turns into a sea of completely different pixels (similar to the color, but I need it to be exact).
I understand that .gif lowers the quality by having to use a much more limited set of colors, which is perfectly good for me - I don't mind having my image's colors slightly changed to match the .gif limits. But I don't want it to dither.
If I truly can't achieve this with MS Paint (which I doubt), what other simple solutions have you got?
I heard something about converting it to a 256-colors bitmap and then transform it to a .gif. I don't think I understood well the instructions: what I did was draw my image, save as a 256-colors .bmp (which converted my colors, which is alright for me), but as soon as I saved it to .gif, the colors dithered.
The simplest answer is going to be "Use absolutely anything other than MS Paint"... I put a couple of free, and low-cost, photoshop alternatives in this answer here to a related question https://graphicdesign.stackexchange.com/a/5901/3327 For something so simple you want to use Paint, I recommend the first one, pixlr, which runs in a web browser, no installation required.
If you really really want to use MS Paint (I guess some people are masochists and it's a valid lifestyle choice? :-) can't spell MS Paint without Pain...), I believe (on Mac right now so can't test) you could do this...
Or, just save as a PNG and run through any of the hundreds of online image file converters