I would say yes. As long as the police accessed the photograph in a legal way, either because it is public, or because someone authorized to view the photo brought it to their attention, then the police could use the photo to try to obtain a search warrant.
A photo of a convicted felon holding a firearm would be enough, in my opinion, for a judge to issue a search warrant for the felon's home to see if there is a firearm there.
My answer to your question is based on the facts that you provide in your question. Additional factual details about your situation could change my answer completely. The law in inherently uncertain and always subject to change.
You're kidding right? I think its a great idea for you to be circulating incriminating photos on the internet. I can't think of any way the police could get those, can you? Take them down immediately. The damage may already be done. The police will have no problem accessing your "friends only" facebook photos. They will not need a warrant to do so. Facebook is not a vault, far from it. You are living in a fantasy land and will get yourself arrested as a result.
I counsel all my clients to close their facebook accounts if they have one. Law enforcement and probation officers DO review these social media sites.
Always assume that your emails, cell phone calls are not private. All postings on the internet are public as well. Don't ever write or say something that you would not want to see or hear in a court of law. Friends and lovers do not always remain so. People can secretly record your conversations with them. Photos taken can harm you in the future. Messages left on a cell phone or answering machine can harm you. Facebook is a furtile ground for law enforcement to get data. Keep your business to yourself.
I am trying to give you a general answer to your question. We do not have an attorney-client relationship by this response on the avvo website. I have not been retained to represent you. I am licensed to practice law in Kentucky and in federal court in this state and the Southern District of Indiana. You need to seek legal advice from an attorney licensed to practice in your area..