Past research has shown that using images on Twitter increases engagement by 313%.
The best way to maximize that increased engagement is to have your photos designed to stand out. Here’s a look at the most important image sizes for Twitter, courtesy of Lindsay:
Profile Photo = 400 x 400 (displays at 200 x 200)
Your profile photo will accompany all your tweets as the main image that people associate with your brand on Twitter. While you want it sized to 400 x 400, keep the image simple, without small text or details that could get lost in the display size of 200 x 200. The max file size is 2 MB and it can be a JPG or PNG.
Header Photo = 1500 x 500
The header photo is significantly larger, with a bit more room to creatively showcase your brand. It will appear on your profile page at the very top and will be sized the exact same on most mobile devices. Since it is a larger image, be sure to use a hi-resolution photo (max is 5 MB) that is either JPG or PNG.
In-Stream Photo = 440 x 220 (minimum)
Photos that land in your stream aren’t as straightforward. The size is a 2:1 ratio, with a minimum appearance of 440 x 220 and a maximum appearance of 1024 x 512. Twitter will collapse your photo into a smaller version that works best in the tweet stream, which could cut off a portion at the top and the bottom. So be sure to vertically center the most important pieces of the image and text in order to avoid losing those in the stream. You can upload photos sized to a max of 5 MB, with a 3 MB max for animated GIFs.
If you’re working through more ways to improve your Twitter profile, check out this article in Twitter’s help center.
Also, if you’re in need of a shortcut image creator that you can use on the go from your phone, I’d recommend PicLab Studio. You can pull in lovely photos directly from unsplash or your own photo albums on your phone, layer text on top, all while working with high resolution images sized just right.