Hover Image Preview by takoyaki

Hover a link to an image and the picture appears right away — no clicking through and going back.

■ Speed
・Zero delay by default; loading starts the moment you hover
・No fades, slides or spinners
・Loaded images are cached, so hovering again is instant
・If a thumbnail-to-original URL guess keeps failing on a site, that rule is dropped for the site to avoid wasted requests

■ Display
・Scaled to fit 92% of your window (configurable), never stretched beyond original size
・Positioned away from the cursor and always kept on screen
・Up to two caption lines below the image:
　Line 1: resolution and scale / camera or phone model / focal length, shutter, aperture, ISO
　Line 2: capture time / location (GPS coordinates, optionally resolved to a place name)

■ Formats
21 image formats (jpg, jpeg, jpe, jfif, pjpeg, png, apng, gif, webp, avif, bmp, dib, tif, tiff, svg, svgz, jxl, heic, heif, ico, cur)
Video (mp4, m4v, webm, ogv, mov; other containers only when the browser can play them)
Thumbnail URLs are upgraded to full size on X (Twitter), Tumblr, Pinterest, Wikipedia, Reddit, Imgur, Flickr, pixiv, YouTube thumbnails and WordPress.

■ Per-domain on/off
Click the toolbar button for an on/off switch for the current site. Turning it off applies to the whole domain including subdomains. Disabled sites get a badge on the icon, and the list of disabled domains is right there in the popup. Alt+Shift+H toggles it too.

■ Keys while a preview is open
O — open in a new tab / C — copy the URL / Esc — close

■ Privacy
The only outbound requests are the preview image itself and the first 256 KB of it used to read EXIF. No browsing history or page content is collected or transmitted.
Only when you turn on "Turn GPS coordinates into a place name" are a photo's coordinates sent to the service you pick (OpenStreetMap or BigDataCloud). That setting is off by default.