RARE, MINI CDV PHOTO CARD JUST less than 1& 1/2 X 2 & 3/4 C. 1880s Full photo OF LITTLE BOY

Very unusual item--a mini- CDV (carte de visite) photo card of 1880s or years before!
The size is one I have never seen before. The photo itself is less than 1 &1/2 inches by 2& 3/4 Inches.On the black thin card stock it is mounted on it tells us--- S. (Sanford) A. Taylor, 158 Fulton St, Brooklyn, NY. There was a photographer there pre 1900 by this name, so a studio picture is what this is..This could be earlier than the 1880s. Many locket photos were made during the Civil War .
At the time photos of faces were cut round or oval from CDVs and made specifically for placing in lockets. (or as pin backs for both men and women.)This is probably the reduced size they used.--The locket photos were not backed with card stock because they went under the glass of the locket frame. Maybe some of this full sized photo reduced as it is here, so small,was also offered to patrons who bought locket photos and regular sized CDVs. Anyway, for sure an obscure step in the making of locket photos where the rest of images were preserved and mounted on small card stock for that purpose. May be the only example known of this type. I can't think of another purpose for this size photo...can you?