Featherview

Featherview opens an image and lets you move through the rest of its folder with the arrow keys, without reaching for the mouse. You can fit, zoom and compare images, view a thumbnail grid, run a slideshow, and send rejects to the Trash from the keyboard. It plays animated GIF, WebP, HEIC and AVIF files, and opens very large pictures such as multi-gigapixel TIFF and PSD files by decoding only the part on screen. Batch conversion resizes and changes the format of a set of images, including ones from albums in Apple's Photos library. It suits photographers and anyone who sorts through folders of pictures.

Requires macOS 14 or later, on Apple silicon or Intel. Featherview is free, but it is not notarized by Apple yet, so macOS blocks the first launch. The README gives a Terminal line that removes the quarantine mark from the app alone, and an Open Anyway option in System Settings for administrator accounts. After that first launch, Finder can show Quick Look previews for the formats only Featherview reads, once you switch them on in System Settings.