I can't think of a situation in which I would say or write "Jack Photography".
"Jack's Photography" could be the name of a photography business or shop.
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I want to write it on my photos, like a signature or watermark.
If it's the name of your business, write "Jack's Photography".
Don't be lazy! Use proper words, not stuff like "dunno"! Also use proper capitalization and punctuation. Otherwise some of us won't bother to answer your questions.