How to make a secret file for pictures

See this --> Hide photos on your iPhone, iPad, or Mac with the Hidden album - Apple Support

Be advised that if you share an Apple ID with someone (which you definitely should NOT be doing), they can find your hidden photos once hidden as easily as you can.

Whatever you do, don't get one of the "vault" apps from the App Store that disguises itself as a calculator or something. Way too many people have come to this forum very upset that the app developer has stopped supporting the app, and they can't get their pictures.

Click ▶︎ Hide your photos for step-by-step instructions.