I intend to take a picture of my bicycle while it's leaning against the wall. Because it's leaning against a wall, most of the background of the photo will be a uniform color. The one caveat is that, because of the angle of the photo, I will not be able to eliminate the ground. Consequently, the background will be composed of two colors – the color of the wall and the color of the ground. Nonetheless, my ultimate objective will be to make the background one uniform color. Another way to put it would be to say that I want to eliminate the background to replace it with one of my choosing.
I haven't used GIMP in a while, and even when I did I wasn't using it to do photo retouching. I have installed version 2.8 on my Windows 7 system. I found an e-book on GIMP, but it is 900 pages long and difficult to navigate. I'm fairly certain, however, that I can use GIMP to accomplish my objective and I'm hoping that one of you experts can tell me how to go about it.