Just having some today see if you can see what is wrong with this image called Photoshop time travel. Somewhere on the blog you will find the original of this but how many things are out of place?
It was great fun to create this image and took a long while to source the components to fit perfectly into the scene. Toning and grading each item to fit the scene in the correct lighting and grain. These are skills that you need to have to perform a photo restoration. If you borrow something from another photo it will need to match the photo it is being put into. If the item is too light it will need darkening and too dark, lightening.
Searching for donor parts to fit into the scene has to be selected for correct perspective. Scale could be adjusted if the resolution was high enough. Grain matches and let the fun begin.