png manipulation

Hi there, I would like to write a program that can analyse png files to assess whether they have any rotational symmetry.

Unfortunately i have no idea where to start! i am aware that opencv can be used to do certain image recognition tasks, would it be appropriate for what i'm trying to do?

Cheers

ps I forgot to mention that this program must work in linux (if that makes any difference?)

you can use libpng (google it) to read the png files and get the uncompressed image data. as an alternative to opencv, check out Intel® IPP - Open Source Computer Vision Library (OpenCV) FAQ | Intel® Developer Zone
I have used the intel IPP libs and they are good.

as for what you want to do specifically, i have no idea.