Uploading pictures

I don't know if it's just me but whenever I have to upload a picture, I have to edit my pic so it's like really small. I was wondering why we can't have more than 150 pixels? In other sites, such as, Twitter, Myspace, Facebook, you can practically upload any size pic and it'll work fine as your default.

I think it would be great if our pictures could be bigger than 150 pixels. What do you guys think?