If a journal requirements for patient's photograph say "Patient Photographic Authorization and Release form (when appropriate)", does this mean I must include patient's acceptance for publication of their photograph? If not, what does "when appropriate" really mean in their statement?
"when appropriate" means that you as a submitter are expected to know if including consent forms is appropriate/required for your research. By stating "when appropriate", the journal says it expects to receive those forms if consent is required for the photographs you are submitting.
Whether this is the case depends on the law, institute-specific regulations, and ethics. It is your job to be familiar with these rules if you work with photographs of patients. In fact, you should probably know what the rules are even before starting research where patient photographs are used.