These are two separate products not related in any way codewise. You would need to actually import the vbgallery content to photopost and make sure everything is fine then uninstall the vbgallery. Photopost vbGallery to Photopost Pro Import Script
I beleive you can turn off in vbulletin section the ability to use the little profile photo thing in vbulletin.
I think in the User Profile Options in vBulletin Options in Admin you can unselect albums to turn off this feature.