All the graphics stuff I've learned over the years was self-taught. I'm definitely no expert, but I think I'm starting to get the hang of it.
I grew up with Paint, like many other people. Then various other tools, eventually to Gimp, and now Inkscape. At first, I really disliked it. As I use it more and more, I'm realizing that I absolutely love working with vector graphics.
Basically, I can create 2d art with objects that I can deform, like in 3d art programs, and then do all sorts of nifty things to them. The best part, when it comes time to export the art to something like games, the SVG format allows me to save at any zoom/detail level. This magic comes from the idea that vector art is generated again and again based on objects and math... as opposed to something as basic as "pixel space". Of course, during the translation from vector-awesomeness to pixels, it gets blocky and pixelated as expected. If I export to a large art file (high def for instance) the vector art will look amazing all while giving me almost no work overhead of screwing with zoom algorithms and stuff like that.
Again, I'm no master at Inkscape, but I'm definitely loving it more and more as I use it more. Maybe I'll post up some more about this later. I hope the Inkscape team fixes up some of these dangling bugs, because I'm using this primarily for mobile app development!