Just a short reply with a few things I think you should fix:
The archer's 'Head shot' ability needs a tooltip! (and probably an icon, its the storm bolt hammer icon right now....not very 'archer-ish')
The archer doesnt take any food to build like the other heroes.
Creeps attack as soon as the game starts (for player 1 atleast) and I don't see why.
Maybe heroes should be produced faster? unless theres a reason it takes quite a while to summon them.
I noticed the terrain is flat, and mostly consists of 2 tiles with nearly no doodads.
Also, as player 1, my camera wasn't at my base for some reason, it was at the top, center of the map.
Only about 3-4 different types of creeps in the map, it would be nice to have a variety.
Edit~
For screenshots, press the 'Print Scrn' button to take one, then open paint (or another image editor) and paste it in (ctrl+v or edit\paste) then save it (preferably as a jpeg as bmp's tend to be huge in file size) then upload and atatch that file to your message as you would any other files.
Also I think that when you import something, it will still be in your map, all of it, so it will take up the same size as if you were to play all of it.