I've looked all over, and read through a few blogs on how you can map a string url into the PictureURL field in the UPS from a BCS connection. Unfortunately it looks like sp1 and on have broken these work arounds such as this: http://spmat.blogspot.com/2010/10/how-to-map-sharepoint-2010-pictureurl.html
Has anyone been able to do this after SP1? Is it even possible anymore? My BCS connection returns a string url of the persons photo, and it populates the PictureURL field correctly but its never used, even after running the Update-SPProfilePhotoStore Powershell command when looking at the profiles they are no pictures and no profiles using that attribute. I know the SYnc is working correctly as my other fields are being populated such as telephoneNumber that i'm replacing. I can't use AD as there is nothing stored in the thumbnailPicture attribute and i don't have access to modify AD.