[otrs] Pasting Images in Ticket Replies

When I reply to a ticket via Firefox, I seem to be able to paste images in the body of the message. Under IE, this does not work. Is this an OTRS feature or some FF add-on that is enabling it? I assume it is within OTRS since the tool knows to upload the image to the /otrs/ index.pl?Action=PictureUpload handle (which makes it an attachment of the article). Hugh