There is an important distinction in this question worth clarifying before anything goes out.
If you are mailing a letter yourself from home, yes, you absolutely need a stamp on the envelope. You pay the postage on your end as the sender. The facility does not accept postage due mail and will not pay for incoming letters. A standard first class stamp handles a regular letter to any US address including FCC Coleman in Florida.
What you cannot send into a federal facility is stamps as an item inside the envelope or package. Stamps are considered a form of currency inside correctional facilities because they can be traded, bartered, and used in underground economies. For that reason, the Bureau of Prisons prohibits sending stamps to inmates. The same applies to blank stationery and other writing supplies. If your inmate needs those items, they purchase them through the commissary using funds in their trust account. Inmates without funds can receive basic writing supplies through the indigent inmate program at no charge.
On family photos, yes, you can absolutely send them. Photos are one of the most meaningful things that arrive in a federal facility's mailroom. The standard that federal facilities accept is 4x6 glossy prints, and they must come through the mail from a sender rather than being brought in during visitation. InmateAid prints photos on proper 4x6 glossy stock and mails them through USPS alongside letters if you want to send them that way without handling the printing yourself.
So to summarize: stamp on your envelope yes, stamps inside the envelope no, family photos yes.