When I do a Google Images search, the results are fuzzy, even if I enlarge with ctrl++. How can I get a higher resolution preview? Perhaps a browser extension or a search parameter?
Image previews (called thumbnails) you see in Google Image search are no bigger than 200×200px. This results in fuzziness you experience when you zoom in your view. It's like you would watch a video file of resolution 426×240 (240p) on 200" TV (eg. not a good idea).
You should go for an extension called Hover Zoom+ which is able to show you full an image behind the thumbnail and all of that without even single click - just point your cursor on the image and wait 0.5 seconds (wait time can be lowered in settings)
Try using Google's "Search Tools" to filter by image size, selecting "Large" for higher resolution results. If you wish to increase the resolution of the preview images specifically, a browser extension like "Google Search 'View Image' Button" can be helpful. This reintroduces the "View Image" button, allowing you to view images in their full resolution directly.