Sgt. Pepperesque photo

I know how to place the photo, but I cannot figure out how to make its color/look consistent with the other figures on the cover.

By @laserjet@mac.com

It sounds like you have two main tasks:

A. Make each imported photo look like it was made with 1960s graphics techniques.

B. Make each imported photo fit in with the others you add.

Both can probably be done by adding a clipped adjustment layer to each imported image. A clipped adjustment layer is an adjustment that applies to only one layer, not affecting the rest. A Curves adjustment layer would be best, but if you’re new to Photoshop it might be easier to use a combination of Brightness/Contrast and Hue/Saturation adjustment layers.

To achieve goal A, you want to try reducing contrast and color saturation, specifically aiming for the tonal and color range typical of printed materials. A starting point would be, for tones, rather contrasty with possibly blocked shadows and highlights (which is how a lot of 1960s photos looked, especially B&W); and for colors restricting the gamut to roughly CMYK because that is what it would be if somebody cut color photos out of a printed magazine.

To achieve goal B, you can for example easily duplicate an adjustment layer that works great for one photo, and clip that duplicate to a different photo. Now you can use the duplicate as a starting point for the corrections for that second photo, because it might need slightly different corrections than the first. Because adjustment layers are nondestuctive, you can iteratively go around and tweak each photo’s adjustment layer as many times as you need until they go together as well as you can make them.

Goodness, I hadn't realized how crude that composite it. 

It's almost certainly done with old fashioned paste-up using an X-acto Knife.

The faces are mostly B&W, and most of them don't look like they belong on the bodies they are linked to.

What exactly are you hoping to emulate?  Do you want a close look and feel of the album cover, or just a multi person composite?

I did this for a university multicultural department several years ago.  It would be much easier to do nowadays with the huge improvements to Photoshop's selection tools and Remove Background.

That's mainly down to how it's lit. If the lighting is very different, it will be very difficult to get it to blend in.

Lighting is the first thing you look at if trying to determine whether an image is a composite.

EDIT: obviously the cover itself is a physical composite with cardboard figures. I hadn't looked at it for a while. So basically anything should fit. Impossible to tell without seeing.