Never mind, as usual, found the soulution as soon as I posted the problem.
Here is my current approach:
Dim tp As New CMS.TreeEngine.TreeProvider
Dim tn As TreeNode = tp.SelectSingleNode(New Guid(myRow("Image1").ToString), "en-US", "mySite")
dim myImagePath as string = UrlHelper.GetAbsoluteUrl(UrlHelper.ResolveUrl("~" + tn.NodeAliasPath)) & ".aspx?maxsidesize=150"