Here the format of the box can help to focus in on the chronology.
Early cards tend to have little text, just the title for the picture, usually on the picture side, and the name of the publisher on the address side.
If your postcard has a stampbox, it may have words or marks denoting what paper was used.
Most Real Photo Postcards, abbreviated RPPC, have information on their backs to help in identifying the manufacturer of the photographic paper that was used by the postcard publisher.
The best way to tell the difference is to look at the Postcard with a magnifying glass.
If the photo is printed, you will see that it is made up of a lot of little dots, the same as a photo printed in a newspaper.