...on whether or not to alter images on the computer.
In the case of your photo, you made alterations to correct the image colors to what you saw on that day. Adjusting the contrast and tweaking the colors is OK in my opinion. However, there are some photographers out there that rely on electronically altering their images on a daily basis.
It isn't very difficult to "Cut & Paste" one image onto another or erase parts of the photo that are not wanted with the aid of a computer! It takes a lot of the true art out of photography when we rely too much on graphic programs to do the work for us.
BTW, I work with graphic programs and publishing software all day in my job - but I would NEVER use it to change my photographs - aside from tinkering with the contrast like you did Nibi.
P.S.(Your photo is really good. I like the contrast on the back rock against the sky and the way the sun highlights the other rock.)