Twitter now offers you the chance of upgrading the background image behind the header picture and profile description. Doing it makes your Twitter account look more professional. Check-out mine at @authorkingsley to see what I am talking about.
Just open your Twitter profile to Edit and you will see the 'Change Header' dropdown button offering 'Choose existing image'. OK, so you need to generate an image first. Here's how.
I suggest you go for the maximum size they allow which is 1252 pixels wide by 626 pixels high. Use whatever graphics program you are familiar with to set up an image, remembering that: a) the default white text of your profile needs a dark area for the bottom half of the image to be readable; b) your photo will be superimposed centre-top, and you need to allow for that. Be aware that Twitter automatically darkens the bottom of any image you upload so as to aid a satisfactory contrast between the superimposed profile lettering and your image.
Some people have managed to merge a head-and-shoulders into the profile full-face picture but the chances of you getting that to align well and look good are very small. So why try?
What I did on my page was to plant a book cover image on either side of the profile picture, each at around 300-350 pixels high. You could use a straight black background on which to mount them. I used a stars background to add a little more interest. Putting cover images is a great way of signalling what you are and what you have produced. You get a preview during the initial phase of uploading so, if things don't look quite right, adjust the source image. Be prepared to slide the book cover images around to look their best.
You know what they say about a picture being worth a thousand words - and Twitter will never let you have those!
That's it! Just upload that image and there you go. If necessary afterwards, change the background image to better match the header, via Settings > Design and then the 'Change background' tab. (You can also upload your own image here, but beware of getting too clever and presenting a busy-busy appearance which can be off-putting. I believe simple background images work best.)
Oh, and if you found this article helpful, please follow me on Twitter. And, as a fellow author, it would be fantastic if you re-tweeted the odd tweet about my books now and then. Thanks a lot!