Currently, it's possible to differentiate between an image uploaded to a profile that is only a source, rather than an actual image of the person. Would it be possible to use this information to prevent setting an image uploaded as a "source" image as a person's primary photo by default? I upload a lot of scanned documents and find it annoying to go back in afterwards and de-select them as the person's primary photo.
I'd think this would be a pretty small change, and it would still allow setting a "source" image as a primary photo; it just wouldn't happen by default.