As a Navy pilot cruising around Asia "in support of the Vietnam conflict", I had the opportunity to collect a lot of Nikon gear at bargain prices. The Navy gave us a beach cabin near Pearl Harbor to live in. I set up a B&W darkroom in the second bathroom and subscribed to all the magazines. I tripped over a technique called "Posterization Processing" where the idea is to reduce tone levels. Ultimately, down to two! If "cooking" can be applied to bad HDR processing, this might be the origin.

I shot a fabulously dull picture of a Mallard duck sharing the takeoff experience with me. I followed the article, cooked it down to monotone and made a print. This is serious "Post Processing" to manipulate an exposure into something it was not intended to be.

The really weird part is that this is one of only four photos people ever paid me for. A fellow Navy pilot came over and offered me $20 for the print I had on the wall. In 1972 you could actually buy something with $20!

Attached here, for your entertainment, is an (automatically exposed!!) JPEG of a forty year old "Post Processed" print I dug out of my files. Is it worth $20?

Long live manipulative, creative Post Processing!

Thanks.
I use Photoshop CC and do not use a template.
I like the images to be the same height for these, but that is not absolutely necessary.
Initial design is on a piece a paper where I do the basic layout, allowing enough room for the borders and the space between the images. Then create the background with a sutable colour to match what is in the image.
The images are imported and placed on the background as layers.
The drop shadows are layer styles (very easy to apply).
Then I do the text, on another layer.

Once you have the idea and the photographs it only takes a few minutes for each one.
Here is a longer story showing what happens around our grand daughters bath time.
Hope this helps.
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I decided that I needed to attach my manure spreader to my Prius.
My Prius does not have a toolbar nor a PTO shaft so I had to resort to Photoshop.
One photo of the Prius in the field, one of the manure spreader being driven by the tractor --> one shot of the Prius spreading manure.

I just set the camera up to take photos every 10 seconds while I set up the shots, then put everything in place and chose the appropriate frame. Unfortunately between the Prius shot and the tractor/spreader shot the wind blew the tripod over so the field of view wasn't exactly the same, but the location was close enough to merge the photos.

Since the trees and the field are the same (the clouds moved a bit) all I had to do was cut out the tractor in the top layer and place the car photo below it to show through the cut out area. A little fine hand work at the back of the car to join the drawbar and the PTO shaft neatly.