Avatar size question

Since I'm now a "super cat", I can have my own custom avatar, correct?
On my CP it shows that the image can be 50x50 pixels or 19.5KB, whichever is smaller. I have a tiny little 50 square image that is only 12.3KB. Can I use a slightly larger version of the image, as long as it doesn't exceed 19.5KB, or does it have to stay under 50 square?
Sorry for my ignorance...I figure it's better to ask for clarification than forgiveness.

I could be wrong, but I think the largest pixel size is 50 x 50. I think that's the amount of space allotted in the template.

Because you would be uploading the image, if it is too big, it won't be accepted, so feel free to experiment.