There are two problems with attempting this pun. First, it's hard to get good contrast with snow and (related, I suppose), the shape may appear to be more 유방 than 눈.
For my mother, and in case the picture is of that poor a quality, Nun means both snow and eye. The picture is not of a snowman but an eyeman. Further complicating the issue is the iris and pupil look a little similar to the naughty bits of a woman's breast.