A partire dal file, potresti scrivere

Dim XDPI As Integer
Dim YDPI As Integer
Open "File.jpg" For Binary As #1
Seek #1, 16
Get #1, , XDPI
Get #1, , YDPI
Close #1
Debug.Print "Ris. Orizz. " & XDPI; " dpi"
Debug.Print "Ris. Vert. " & YDPI; " dpi"