imagebutton clicked in a datagrid

[EMW]

Hi,

I have a datagrid with four template columns.
After the user selects something in a listbox, the datagrid is filled with
pictures by using an imagebutton.
I gave the image argument part the string containing the url of the picture.

What I now want is when the user clicks on the picture, a new browser window
opens showing that picture in its real size.

How can I do this in VB.NET?

thanks,
Eric