any small c++ library can do image recognition?

[aj3423]

Hi,
I'm writing something like AutoIt, which can recognize image from the screen. I need it to read a image, such as a .png file, then search it on the screen to get the match position.
it's not necessary to be matched 100%, maybe the image is a spark or a fire, so they are animating, the library should be capable of fuzzy matching.
I googled a lot and found opencv, I've not tried it yet but it's too huge(200mb+), still downloading it now.. I just need the search function and trying to find some small library

Any idea?

Thanks