I'm not sure if this is an experiment or a feature that's currently rolled out. Google Image Search for mobile has a new interface that replaces pagination with infinite scrolling, just like the desktop interface. You can see a lot more images without having to swipe and it's much easier to find great search results.
Google also added an option to "scroll to top", but this is more useful if you use Android. iOS has a built-in feature that scrolls to the top of the page (or the current view) when you tap the status bar.
When you select an image result, you'll probably see a new interface that focuses on the image and makes it more obvious that you can swipe right/left to check to other results.
Unfortunately, just like the new desktop image search, the redesigned mobile interface replaces snippets with page titles and removes the file size (in bytes, not pixels).