{ Alternative Text for a image of a TWebBrowser }
procedure TForm1.Button1Click(Sender: TObject);
var
 HTMLDocument2Ifc: IHTMLDocument2;
 HTMLSelectionObjectIfc: IHTMLSelectionObject;
 HTMLTxtRangeIfc: IHTMLTxtRange;
begin
 HTMLDocument2Ifc := WebBrowser1.Document as IHTMLDocument2;
 HTMLDocument2Ifc.execCommand('InsertImage', False, '');
 HTMLSelectionObjectIfc := HTMLDocument2Ifc.selection;
 if HTMLSelectionObjectIfc.type_ = 'Control' then HTMLSelectionObjectIfc.Clear;
 HTMLTxtRangeIfc := HTMLSelectionObjectIfc.createRange as IHTMLTxtRange;
 HTMLTxtRangeIfc.pasteHTML('<image alt="Hello" src="c:\test.gif"> ');
end;