hoverglass

Hover a thumbnail, see the real thing.

Hoverglass expands an image or video next to your cursor when you hover its thumbnail, and follows the cursor as you move, repositioning to stay on screen. It plays YouTube and Twitch inline, handles Reddit videos and galleries, and can pin a preview to the center or detach it into a draggable picture-in-picture window. One Manifest V3 codebase covers Chromium and Firefox.

VIEW SOURCE ↗

A Reddit feed with a hovered thumbnail expanded into a large, fully readable preview beside the cursor.

what it does

Hover to expand — full-size media appears beside the cursor and follows it, repositioning to stay on screen.
Hover to play video — YouTube and Twitch links open an autoplaying muted player; direct .mp4/.webm/.gif media plays too.
Reddit videos and galleries — v.redd.it posts play inline, and gallery posts step through with the arrow keys.
Center to inspect — the pin key (default Space) sticky-centers the preview for a focused look.
PiP / free-flow — the PiP key (default P) detaches the preview into a floating window you can drag while the page scrolls underneath.
Zoom, pan and resize — +/- zoom in both center and PiP, wheel zoom in center mode, cursor panning once zoomed past the viewport, and drag-corner resizing.
Smart resolution — srcset, wrapping links, lazy-load data attributes and CSS background images, plus an editable rule set for YouTube, Twitch, Twitter/X, Imgur, and Wikimedia.

screenshots

The preview at a mid size beside the cursor, with the feed still readable behind it.

The preview zoomed large, filling most of the window for a close look.

The preview detached into a small picture-in-picture window in the corner, with the page live behind it.

built with

TypeScript
esbuild
MV3
Vitest

get it

VIEW SOURCE ↗