[Stocker]

Have you made sure the vee-angle of the belt exactly matches the vee-angle of the pulley grooves? My only other thought is that in spite of your efforts, the pulleys might not be in perfect alignment. Can't tell by the pic, sorry.

Have you tried rubbing a bar of soap against the belt with the engine idling? It won't fix the problem but will often stop the squealing for a short time. Just one more way of proving that's the problem belt. Usual disclaimer about keeping clothing and fingers away from moving fans, belts, & pulleys....