ArcGIS Pro 3.4 API Reference Guide
ArcGIS.Desktop.Mapping Namespace / StyleItem Class / PreviewImage Property
Example Version

PreviewImage Property
Gets the preview image for the style item.
Syntax
public ImageSource PreviewImage {get;}
Remarks
The size of the preview image is determined by the PatchHeight and PatchWidth properties of the style item.
Example
Create a Swatch for a given symbol
//Note: call within QueuedTask.Run()
CIMSymbol symbol = SymbolFactory.Instance.ConstructPointSymbol(ColorFactory.Instance.GreenRGB, 1.0, SimpleMarkerStyle.Circle);
  //You can generate a swatch for a text symbols also.
  var si = new SymbolStyleItem()
  {
      Symbol = symbol,
      PatchHeight = 64,
      PatchWidth = 64
  };
  return si.PreviewImage;
Requirements

Target Platforms: Windows 11, Windows 10

ArcGIS Pro version: 3 or higher.
See Also