I can't post to here, so I'm adding my own thread: www.visualwebgui.com/Developers/Forums/tabid/364/forumid/-1/threadid/47000/scope/posts/Default.aspx
I'm not sure why it isn't reproducable on Gizmox's end, but it definitely is over here. You have to use IE (I've tested it in IE6 and IE8). It seems fine in Firefox (haven't tried Chrome).
I have a simple project that I put together in 5 minutes, if you want it. But, it was as simple as:
1. Creating a new Visual WebGUI application.
2. Plopping a Toolbar on the form (all defaults - I forget if I docked it to the top on my own or it did it automatically).
3. Adding 1 toolbar button (again, all defaults, except I set Pushed to true).
4. Placing a gif in my Resources/Images folder (16x16)
5. Adding Themes as a reference and selecting Facebook.
6. Adding this line of code to the constructor of Form1:
this.toolBarButton1.Image = new Gizmox.WebGUI.Common.Resouces.ImageRecourceHandle("myimage.gif");
Change the specific page to Form1.wgx, compile, run, and you have a button with a cut-off image.