Hello Louise Burke,
This information can be gathered by using Datafeeds. The particular table that will have profile photo information is dUser. In the column labeled "has_image", if the user has a TRUE, then that means that the user has uploaded a profile picture. If it has a FALSE, then it means that they haven't.
For other profile field data, you can look at the flCommunityMemberProfileField table. This table provides a record of member profile fields and whether a member has data in them.
Here is some documentation on how to access Igloo Datafeeds from:
Please let me know if you have any questions.