A: 

It's case sensitive, make sure you're still setting the Src property, capital S...and just remove the src="" from the tag itself so there's no confusion by anyone reading it later:

Me.imgPicture.Src = theUrl
Nick Craver
Nick, please note that I have used the case sensitive syntax in the codebehind file - namely, Me.imgPicture.Src = theUrl but the problem is that the compiler cannot "see" this: I get this during the build:
John Galt
error BC30456: 'imgPicture' is not a member of 'Zipeee.frmDisplayAd'.
John Galt
@John - is the image wrapped in another control, another naming container?
Nick Craver
+1  A: 

the <asp:imagebutton onclick="..." > is for a server method (code behide).

try with onclientclick

y34h
+1  A: 

Hi,

in asp.net imagebutton there is no property class change it to cssclass="PopBoxImageSmall"

then it will work.

Moksha
Thanks to y34h and Moksha. All I really did was change to onclientclick and cssclass keeping the context of the <asp:ImageButton> as it was. I still don't see how to dynamically construct the HTML content from the codebehind for a standard <img> tag but the web control for ImageButton is now working with this fancy Javascript so I will settle for that and move forward for now. @Nick, in the .aspx.vb codebehind file, Me.imgPicture.Src (where imgPicture is based on <img id="imgPicture"...etc.) cannot compile because imgPicture is not a member of the namespace.class). It'there, but how to set?
John Galt