Try this
VB Code:
  1. Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As Any) As Long
  2.  
  3. Private Const WM_PASTE = &H302
  4.  
  5. Private Sub Command1_Click()
  6. 'To Paste Picture From PictureBox/Clipboard to Rich Text Box
  7. 'Note:  Will not work with Icons (.Ico files)  It does work with BitMaps and Metafiles
  8.     Clipboard.Clear
  9.     Clipboard.SetData Picture1.Picture
  10.     SendMessage RichTextBox1.hwnd, WM_PASTE, 0, 0
  11. End Sub