What sizes will your Twitter profile image appear on Twitter?(April 2014 Update: Twitter rolled out a new design across the platform, all the templates on this site are optimized for the new design)
The next size is 73 x 73 pixels.
This size will be shown above the description on your Twitter header image.
The next size that your twitter profile image will be shown at is 48 x 48 pixels.
This size will be shown most often. every time you tweet a new post, it will be shown next to the post.
The smallest size your profile image will appear is 31x31 px.