ArcGIS Pro 2.7 API Reference Guide
SetSourcePath Method
Example 

ArcGIS.Desktop.Layouts Namespace > PictureElement Class : SetSourcePath Method
String
Regenerates the picture using the new file path to a picture on disk. This method must be called on the MCT. Use QueuedTask.Run.
Syntax
public void SetSourcePath( 
   string URI
)
Public Sub SetSourcePath( _
   ByVal URI As String _
) 

Parameters

URI
String
Exceptions
ExceptionDescription
This method or property must be called within the lambda passed to QueuedTask.Run.
Example
LayoutProjectItem layoutItem = Project.Current.GetItems<LayoutProjectItem>().FirstOrDefault(item => item.Name.Equals("Layout Name"));
await QueuedTask.Run(() => 
{
  Layout layout = layoutItem.GetLayout();
  PictureElement picElm = layout.FindElement("Rectangle") as PictureElement;

  picElm.SetSourcePath(@"C:\Some\New\Path\And\file.ext");
});
Requirements

Target Platforms: Windows 10, Windows 8.1

See Also

Reference

PictureElement Class
PictureElement Members