Paint.NET ICO FileType

Paint.NET ICO FileType adds proper multi-image .ico support to Paint.NET.

What it does#

• opens every decodable ICO frame as a named layer,
• handles PNG-backed and legacy BMP/DIB-backed icons,
• writes real multi-image ICO containers,
• exports common icon sizes from 16 px through 256 px,
• preserves transparency and can keep aspect ratio with transparent padding.

Install#

Download paintdotnet-ico.zip from the shared rolling Latest release. The ZIP contains separate adapters for Paint.NET 5.2+ and Paint.NET 5.1.x plus Install.bat.

For per-user installs, the helper uses:

Documents\Paint.NET App Files\FileTypes

Classic installs can also use:

C:\Program Files\Paint.NET\FileTypes

Restart Paint.NET after replacing a plugin DLL.

Two adapters, one codec#

• Paint.NET 5.2+ uses the newer PaintDotNet.FileTypes API and .NET 10.
• Paint.NET 5.1.x keeps a compatibility adapter on the classic FileType API and .NET 9.

The actual ICO codec is shared plain C# with no external image-package dependency.