.syn file: how to open it on Windows

4 Windows apps register the .syn extension. Install one of them to open the file with a double-click.

XnView MP
Professional Image Viewer & Photo Management

Proprietary 1.12.2.0 436.9K ↓
SageThumbs
A powerful shell extension allowing to preview enormous amount of image formats directly in Windows Explorer.

Open source 2.0.0.23 14.6K ↓
Sublime Text 4
Sublime is a sophisticated cross-platform text editor for code, markup and prose.

Proprietary 4.0.0.421500
XnView
Best Photo Viewer, Image Resizer & Batch Converter for Windows.

Proprietary 2.52.7