Detlik: *snip*...also so which program I should use? You recommended me a lot of different programs and I have no idea which to use...Photoshop,gimp,coral,etc...
Overall I recommend GIMP. It's free, and it's great (so you only lose time if you try it and don't like it). I've GIMP, Photoshop CS4, and PaintShop Pros 6 and 9 (all legit, some crazy expensive), but of those I only use GIMP nowadays. If you just want to doodle with your mouse, pre Win7 MS Paint was great for that (Win 7 MS Paint is bad at that to me, it antialiases everything and I don't want that in my MS Paint). There are other programs too for specific stuff like if you want to make sprites or something. You can make 'em with those fancier programs too, but having a limited, specific set of functions can be really helpful, like there was this old horrible sprite painting program that had practically no tools, always zoomed in really close and all you could do was make 256 color palettes and change the color in a single pixel at a time and I loved it. It all kind of depends on what you want to do and how much you're willing to use general skullduggery to get things done.
Between Photoshop and PaintShop Pro, I recommend PaintShop Pro (since you're not trying to become a professional artist that might need to follow some set standards). It's cheaper, has enough features and at least the versions I have handled vectors a lot better than Photoshop (since they've that Illustrator program for that or something). It seems like they've changed the name to PaintShop Photo. I live in the past, maan.
/edit: ...and since I live in the past, my info on stuff might be horribly outdated. Anyway, I think GIMP is great.