Hi Chris,
I am not familiar with Stimulsoft (yet), but from your description I don't see any problems with using an HtmlBox in your solution. As you were able to the the image shown in a PictureBox, you can as well have it shown in a HtmlBox.
Using PictureBox versus HtmlBox to display an image is almost identical, once you have got the GatewayReference:
reference = New GatewayReference(Me, "submitimage")
PictureBox1.Image = New Gizmox.WebGUI.Common.Resources.GatewayResourceHandle(reference)
HtmlBox1.Url = New Gizmox.WebGUI.Common.Resources.GatewayResourceHandle(reference).ToString()
And to continue, I already uploaded a Wiki sample showing how to print the contents of a specific HtmlBox only and you can find that sample code here.
Hope this helps,
Palli