Won't work more than 1 time.
Dota 2 randomizes certain pixels by a small degree each time you load a game.
So ImageSearch wont work more than one time
What you want to do is:
PixelSearch, FoundaX, FoundaY, 870, 657, 888, 730, 0x3B3635, 10, Fast ;Pick Hero
if ErrorLevel = 0
MouseClick, Left, 875, 680
When hero select loads press 'x' or any key you set it as it will search for hero beginning with tro and pick troll warlord.
You might be able to shorten the Sleep to 300 but to be absolutely sure it reaches troll warlord I have it at 500 this means that in 0.5 seconds you pick troll warlord (if you remember to press the button required)
Enjoy, I only did this because I already had a similar code ready