<PackageReference Include="System.Drawing.Common" Version="9.0.6" />

PaletteFlags

public enum PaletteFlags
Specifies the type of color data in the system palette. The data can be color data with alpha, grayscale data only, or halftone data.
namespace System.Drawing.Imaging { [Flags] public enum PaletteFlags { HasAlpha = 1, GrayScale = 2, Halftone = 4 } }