CSO2 is a lightweight Windows utility that displays PNG images as transparent, always-on-top overlays. It is designed for quick visual reference, graphic comparison, and desktop overlay workflows.
If you just want to use CSO2 without installing Python, download the prebuilt executable from GitHub Releases:
- Go to the repository page → Releases
- Download the latest
cso2.2.exe(or the provided ZIP, if available)
- True PNG transparency support
- Frameless, always-on-top overlay windows
- Mouse wheel zoom with smooth scaling
- Horizontal mirror toggle via keyboard arrows (Left/Right)
- Click-and-drag window positioning
- Right-click or
ESCto close a window - Multiple independent overlays per session
- Set cso2.2.exe as default software to open .png files, or
- Drag and drop a PNG file onto the executable, or
- Run from command line:
cso2.2.exe "C:\path\to\image.png"