Border on icons

I have my blog up and running beautifully!! 🙂 http://blog.theweddingnetwork.com.au/about/

but now i see my icons with borders around, like the other images on my theme.

i know its the css file i have to edit, but which one? can someone please point it out?

and is this what I should add to the css:

img.wp-smiley {border:none;}

Help appreciated 🙂