Can someone please explain what a composite photo is and what it's used for?
Literally, what it says. An image made up of several.
For various reasons - art, deception, requirement.
Yeah but is it like putting together 3 transparencies? Do you use the whole layer? What would be a requirement?
Back in film/development days, nifty things were done with film. Nowadays - it's programs like Photoshop.
With Photoshop , you can use digital 'layers' - they are just as you think they would be.
A 'requirement' would be, for example - adding an absent person to a group photo for completeness.