Dear vagelis28,
The value of "src" should be:
src="http://www.mysite.com/CuteSoft_Client/CuteEditor/Images/emteeth.gif"
or
src= "/CuteSoft_Client/CuteEditor/Images/emteeth.gif"
Please set URLType to "Absolute" and try it again:
<CE:Editor URLType=Absolute id="Editor1" runat="server" ></CE:Editor><BR>
Thank you for asking