Hi,
Try to copy something from word, and then run this code in a C# project:
object rtfData = Clipboard.GetData(DataFormats.Rtf);
Clipboard.SetData(DataFormats.Rtf, rtfData);
You will see that Word puts data in Clipboard in RTF format.
In order for you to make the same thing, you must put into clipboard RTF data format.
In your example if you paste in word, it will copy the text from Clipboard, and if you paste in Paint it will copy the Image.
Every external program parse the data from Clipboard in his own way.
Hope this helps.