Good find on the data, the database I access didn’t have this building at all because it’s pre 1900 construction-I had wild-carded my search and it showed no buildings in that area that fit the height, so I was almost certain w/o the address etc that it was pre 1900 and that was right too- 1892
The architects were Renwick, Aspinwall & Renwick, so I was wrong there, but if this is the same Renwick I have in mind JAMES Renwick, he was the architect of Grace church and St Patrick’s

The budget explains the somewhat plain building and in the back of my head the thought came to me the panels had some connection to Della Robbia and children, possibly the owner’s daughter- they are unusual.
I think you have another photo of a building with some Della Robbia carvings- babies swadled tightly in wraps, it was originally a foundling hospital and as I remember it was up somewhere in the 20′s on the East side, NY hospital
This was New York Lying-In Hospital (1899) in the early 20th Century, 60 percent of all NYC hospital births were here.

static.flickr.com/60/186830324_4e162f1ebe.jpg
static.flickr.com/64/186830325_15654e6192.jpg?v=0

The New York Society for the Prevention of Cruelty to Children was organized in 1875 in response to a law passed in that year by the New York State Legislature authorizing the establishment of branches of this child-welfare organization in each county of state. The organization was established to investigate cases of cruelty to children under the age of 16, to care for abused children, and to assist in the enforcement of laws established to protect children.

The Society’s building on the southeast corner of Park Avenue South and East 23rd STreet was begun in 1892, the same year that work began on the adjoining United Charities Building. It is clear from the restrained exterior design that the Society for the Prevention of Cruelty to Children did not wish to expend a great deal of unnecessary money on the embellishment of their new headquareters. The building has an unadorned stone base, a simple yesllow brick upper facade, and modest terra-cotta detail. The major ornamental features are located on the seventh floor, where terra-cotta panels with figures of children represent the original use of the building. These panels are modeled after those designed by Andrea Della Robbia at the Ospedale degli Innocenti in Florence. This terra-cotta work was created by the Perth Amboy Terra Cotta Company. The main entrance, located in the center of the Park Avenue South elevation, was originally set within a projecting two-story portico with freestanding columns, but this entrance has been cut back to the building line. The building has been converted into apartments.

100 e 23rd comes up on the corner of PARK and shows this;

Number of floors: 16 Building Gross Area: 145299 sq. feet
Residential Units: 179 Total # of Units: 190

Anyway, something isn’t right because the database for that intersection says there is that 16 story building at #100 and a 12 story building but nothing around 7 or 8. I’ll look again when I have a moment.

Park and 23rd, about 20 stories hight with a fairly large overhanging rooftop cornice right?
Google maps gets in pretty close but not quite close enough to see smaller details.

The style says Stanford White to me, I don’t find any building over 12 stories high in the database there, so it may be older than 1900.

These figures are very good quality, this was a top notch project which is another reason I suspect White. Next time you are up there let’s see more of it and the exact entrance address if possibe and I’ll look again.

I believe this is the building;
(deleted)