Posting a picture

Hello and thanks for taking my question. I see a lot of people posting captions on their pictures letting the viewers know it's of them and some of their friends and I really never know which usage is correct. Some people use "My friends and me" and other use "My friends and I". I tend to think it's my friends and me, but does it really matter being that this is not a complete sentence and does nto contact a verb or subject? I mean, the subject and verb are implied in the picture, but really, which is correct? I know that it would sound strange to post a picture with just I. Thank you. John