Review of Phototonic powered by the Slant community.
Phototonic is a fast and functional image viewer and organizer, inspired by the traditional image viewer design (i.e. thumbnails and viewer layouts)
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Pros
Pro Clean and functional UI
Beside being pretty clean and easy-to-use, the UI is also pretty fast.
Pro Can be easily keyboard driven
Lots of pre-defined keyboard shortcuts.

Pro Highly customizable
Lots of options to personalize your experience. You can set Photonic to fit images by width and height, or width or height; rotate according to Exif orientation; show/hide image name in viewer; adjust space between thumbnails; adjust delay between slides.
Cons
Con No Dark mode
And not a lot of customization available.
Con No WebP image format support
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