Digital art design, renderings, signatures and anything art related. Upload pictures of your newest work or ask for feedback. Post graphics requests or discuss art in general.
Big enough that if you were sitting next to me I might stab you with a ballpoint pen. Unless you came over for dinner, in which case I have a lovely 8" chef's knife.
Make it a transparent .PNG file and you won't have pixelly edges, or any quality loss at all, really. And yes, please, make it smaller. Much smaller. That text at the top can easily fit somewhere else, I'm sure.