@craigreilly
Hi,
In my case, I'm pretty sure it's impossible it comes from Web Client, we never used it on this location, and this is a new 3cx install.
IMO I bet more on google contact, but no idea how it links with 3CX
The client will first look at the profile picture from the PBX. It not present it will then look into the local android phonebook: first - from contact with same extension number, then if it is not present - from contact with same e-mail.