Searching dataset for Constellation detection
If actual photographs are not required, Stellarium could render a suitable set of reference images.
Use the Perspective (gnomonic) projection for the closest match to a photograph, and display only the features you want.
Its scripting capability may help you avoid repeating some manual operations.
Here are a sample pair of Stellarium images.
The first has only synthetic stars, which the online plate-solving service Astrometry.net successfully recognizes:

The second is the same part of the sky with only constellation labels and boundaries:

The unlabeled region between Ophiuchus and Scutum is Serpens Cauda,
part of the only discontinuous one of the 88 standard constellations.