Your gift of a photo would probably be presumed to be permanent and non-revocable, since you gave it with no strings. Even if you could revoke it, it would never be less than a non-exclusive license to the person you gave it to.
A copyright can only be transferred in writing, so if you transferred that as well as the copy of the photo itself in writing, I don't think that would be revocable either, even if you somehow claimed you could revoke it. If you transferred a copyright orally, that would probably be considered a non-exclusive license.
Why am I using the word "probably"? Because legal analyses always depend on the situation's specific facts, and here your facts seem hypothetical and unclear.
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