I can probably help, I know a lot about medals. What makes you think they're from the late 1800s, early 1900s?
Dear Mr. Fettig,
Thank you for posting your request on History Hub!
In order to possibly identify the origin of the military uniforms and decorations from the postcard image, you will need to determine the specific country and branch of service that are represented. We suggest using the other details from the postcard as a starting point for your research. For example, the language of any text in the image, printed on the reverse, or written by the sender may point to a country of origin for the image, as might the name of the photographic studio or printer where the image or card were produced. A postmark and stamp could also be useful in determining a possible source and timeframe for the postcard. Additional details from the image itself might also help narrow down your search. If there are any buildings, landmarks, weapons, vehicles, or objects in the image, for instance, then they might help point you in the right direction. Details from the uniforms themselves should also be considered, including the cut of each piece, the style of hats and boots, other decorative elements like braids or epaulets, and so forth.
We also suggest that you search WorldCat for relevant books or scholars on the subject, and a reference librarian at your local or university library may also be able to guide you to additional useful resources.
Finally, the style of the postcard and photograph themselves could also provide some clues for you to follow. The Smithsonian provides some online information about Postcard History and Dating Postcards, and the Library of Congress offers a Research Guide to Postcards, too. You may wish to contact them or the National Postal Museum to see if they can offer you any further assistance.
We hope this information is helpful. Best of luck with your research!