Older people map less...there are exceptions, just not many.
And you make heightmaps yourself in a paint program!
Ahh... But I am no artist, without the slightest idea how the heightmap system works.
I said before...a white pixel = high point, a black pixel = a low point, so making an image that is white in the center and fades out to black at the edges will give you a mountain shape, use smudging and stuff to make it a rough uneven mountain. That's it!
Here, an example which would make a jagged slope all the way around to near the top right corner where it would then drop back down again
(dark colors->light colors->dark colors)