I just finished a new banner ad for my wife's dream interpretation site, MyDreamVisions.com.
I did the ad using Inkspace under Ubuntu. Open source drawing programs have come a long way. The current version of Inkscape works pretty well. With a little thought, I can create just about any image I can imagine (the limiting factor, in my case). The next version is a major upgrade and is adding a whole bunch of new features. I hope they are going to improve the user interface, which is a bit of a hodgepodge. Things pretty much work, but there are odd bugs and inconsistencies throughout.
But, like I said, it works well enough and it is possible to draw what I want to.
Here is the banner ad I made: