Here is how to setup embedded base64 encoded image (provided the image is png):
<asp:Image runat="server" ID="foo" />
foo.Attributes["src"] = "data:image/png;base64," +
Convert.ToBase64String(myByte);
Again - this should be avoided; you can't cache images served like this; so if you really really want to serve images from db you should consider external handler/page to serve them (and set up caching on that handler).