What's up with my twitter icon?

[Name]

Every time I upload a new twitter icon, there's always this box that limits the size of my icon. This started happening when the new twitter came up. I'm wondering why my other friends' icons can be large while mine has a box limit? It's so annoying how my icons always turn out so small. Is there a way to adjust or change this? please help

[Charles L]

Change the setting of your twitter account, plus you must have to take the best size image to update twitter icon.