How to sharpen group badges?

[MMXII]

When I look at the group badges that you use here on invisioncommunity.com, they look pretty sharp to me.

However when I upload images in the group settings, the badges in the postbit look either way too big (when I use images with a higher width/height in pixels, e.g. 500x200) or very blurry (low width/height in pixels, e.g. 50x20).

How can I make my group badges look as sharp as yours?

Edited May 7 by MMXII

[opentype]

It’s a custom.css rule to limit the size while uploading a larger image. 

.cAuthorPane .cAuthorGroupIcon {
	max-width: 60px;
}

 

[MMXII]

Oh, I was lookig for group options to resize the badge and totally forgot about custom CSS. Thanks!