If you don’t like the new Google Image Search interface, you can’t go back to the previous interface. Fortunately, Google still includes a link to a much older interface without infinite scrolling, but with useful information like the file size and a page snippet.
Infinite scrolling makes it difficult to get to the bottom of the page because Google continuously loads new image results as you scroll down. The best way to find the link that switches to the old interface is to press “End” on your keyboard (Fn + Right Arrow if you have a Mac) and click “switch to basic version”. Google doesn’t remember your setting, so the switch is not persistent.