So to paste Image In Rich Edit Box for Windows 10, Windows Phone 8.1 First Drag and Drop a "RichEditBox". Like this:
  1. <RichEditBox x:Name="rtbox"
  2. Width="500"
  3. HorizontalAlignment="Center"
  4. VerticalAlignment="Center"
  5. KeyDown="rtKeydown" />
Now Double Click the "rtKeydown" event .so to achieve our task we need get the content from Clipboard.and read the image content from DataPackage of clipboard like this:
  1. private async void rtKeydown(object sender, KeyRoutedEventArgs e)
  2. {
  3. if (e.Key == Windows.System.VirtualKey.V && e.Key == Windows.System.VirtualKey.Control)
  4. {
  5. var dataPackageView = Windows.ApplicationModel.DataTransfer.Clipboard.GetContent();
  6. if (dataPackageView.Contains(StandardDataFormats.Bitmap))
  7. {
  8. IRandomAccessStreamReference imageReceived = null;
  9. try
  10. {
  11. imageReceived = await dataPackageView.GetBitmapAsync();
  12. }
  13. catch (Exception ex)
  14. {}
  15. if (imageReceived != null)
  16. {
  17. using(var imageStream = await imageReceived.OpenReadAsync())
  18. {
  19. var bitmapImage = new BitmapImage();
  20. bitmapImage.SetSource(imageStream);
  21. rtbox.Document.Selection.InsertImage((int) bitmapImage.PixelWidth, (int) bitmapImage.PixelHeight, 0, Windows.UI.Text.VerticalCharacterAlignment.Baseline, "Image", imageStream);
  22. e.Handled = true;
  23. Clipboard.Clear();
  24. }
  25. }
  26. }
  27. else
  28. {
  29. //For Exception
  30. }
  31. }
  32. }
Now Run the App.its completed. output will be like this:
Copying the image from Browser.
Browser
Pasting in RichEditBox.
RichEditBox
Please comment below for any doubts.