For some reason, Twitter did not make putting in a header photos easy. Twitter tells you that the correct Twitter header size is 1500 x 500 pixels. But, when you upload an image that size, Twitter still automatically enlarges it, cuts off the edges, and decreases the quality. A triple whammy! I think it has something to do with trying to make the header optimize for different devises.
I did some research* and came up with 5 easy ways to Optimize your Twitter Header Image and I used these five tips to you step-by-step how to convert your Facebook Cover Photo into a Twitter Header Image.
If you’re still not happy with the quality, I have more more quick tip, short of starting everything over with much bigger images.