download shup from here:
http://shup.com/
-and install it
open reaper and load your fine theme.
Use
shup to capture the screen shot (very easy to do).
Tweak it if necessary and then press the icon that looks like
an arrow point up.
A few moments later you will hear a blippy-beep sound, which is
shup letting you know that the image has been uploaded to
stashbox and the url has been copied to your clip board.
Once you hear that, type
[img] in you theme post.
Then press [ctrl]+[v] to past the url and then type
[/img]. And that should do it.
A nifty new screeshot of your nifty new theme embedded into your
post.
greetings
.tallis