Media Magnifier od Therin

Media Magnifier replaces Firefox's image and video viewer with a zoom-and-pan tool.

Scroll to zoom smoothly toward your cursor (to any zoom level), then click and drag to pan. It works automatically on standalone media, and on media embedded in any web page via a right-click "Magnify media" menu item.

Features:
- Smooth scroll-to-zoom toward the cursor, to any zoom level
- Click-and-drag panning; videos keep playing while you zoom and pan
- Works on images, animated GIFs, and videos
- Automatic on media opened directly in a tab; right-click "Magnify media" anywhere else
- Keyboard shortcuts: +/- to zoom, 1-9 to jump to 100%-900%, 0 or F to fit, arrow keys to pan, P to toggle pixelated rendering for inspecting individual pixels
- No data collection, no tracking, no network requests

Press H or ? while viewing media to see the full list of shortcuts.