Resizing photos

I want to adjust the size of photos that users upload to my website.

What could you do to the code below to adjust the size of the photos written to the website?

function showuserGROUPphotos(varfilenamethumb, varfilename, varimgtitle)
Set fs=Server.CreateObject("Scripting.FileSystemObject")
varpath = server.mappath("usergroupphotos")
varfilepath = server.mappath("usergroupphotos")

varpath = varpath & "\" & varfilenamethumb
varfilepath = varfilepath & "\" & varfilename

If fs.FileExists(varpath) = true Then
varfilenamethumb = varfilenamethumb
Else
varfilenamethumb = "nopic.jpg"
End If
If fs.FileExists(varfilepath) = true Then
varfilename = varfilename
Else
varfilename = "nopic.jpg"
End If

showuserGROUPphotos = "<a href=""showaphoto.asp?gid=" & session("groupid") & "&vpath=usergroupphotos/" & varfilename & """><img src=""usergroupphotos/" & varfilenamethumb & """ class=""imgborder"" alt=""click photo to enlarge""/></a>"
end function