Hey Patrick:
I don't think it would be the best solution before considering all possibilities, but you could add a new lead field and fill it with the link to the user's photo, with a default fallback that makes sense.
Then on the LP itself, you could add an image with
<img src="{{lead.Headshot:default=http://example.com/fallback-image-for-anonymous-visitors.jpg}}">. Then you'd have to set a process in place to have headshots only at certain proportional sizes, and that should work so long as the user is cookied before entering the page.
But there might be better ways to do this. I only add lead fields as last resorts, when I know the field is going to be significantly more than a one-time use. Unused lead fields are wasteful.
Best,
Edward UnthankMarketing Operations Specialist
Yesler