You may have your preference to another program and if you're happy with
it and understand how it works then stick with it. Lot's of tutorials
exist on the internet and I suggest using your favorite search engine
to find and go through a few. Post your own tutorials online for
other users to try. You can post a review on your most or least
favorite software too.
We'll look at preparing an image for print later but manipulating images could
be a series of books all in itself!
Tip:
Open source does not mean lower quality. For a List of free
software that is often every bit as good, and often better, than
'paid for' software have a look here
http://www.opensourcelist.org.
