On H3rmit's profile page, I see the pic at about 3.5" x 4.125". I'm sure that would change if I were using a bigger or smaller monitor.

When I copy the image into Photoshop, it calls it 309 x 395 px, 4.292" x 5.486" @ 72 px/in. When it's displayed in Photoshop at "100%" magnification, though, it actually measures 3.875" x 4.625". I'm guessing that the last part may be because I'm using a larger monitor (20") than whatever Photoshop considers standard.