People like looking at photos. And specifically, people seem to like staring at photos posted onto Twitter. So the company behind the 140-character service has decided to make the experience of using its website for the purpose of checking out pictures a lot more enticing than it was before.
And this has happened through a simple (if well overdue) change: the photos are now bigger. That's it. The size of the images in your stream has been enhanced, which means you'll probably resort to clicking a picture in order to see a bigger version of it a lot less in the future.
The same treatment has thankfully been applied to multi-photo displays, as evidenced by the screenshot below.
The new multi-photo viewer emphasizes each image more than before, while also actually having grown bigger in size. Twitter says these changes will make your timeline "more immersive".