I came across this setting today which solved an issue I have been having with Twitter not displaying high resolution images. Whenever I loaded Twitter, I would see blurred images that contained a prompt to that I had to click to see the image. Annoying and only seemed to happen on Safari (not Chrome or Edge).
The fix is to tweak the setting shown in the image below – hopefully it’s not blurry :-). You need to deselect (uncheck) the Data Saver option. This will allow Twitter to download higher resolution images on page load, instead of giving you the blurry version. Of course if you are on a low bandwidth connection, you may want to leave this setting checked.