Looks like it takes considerable "artistic license" to deviate from the photos. Every person getting turned into a stereotypical "caucasian" type is the most noticeable (and most problematic), but also the spotted cat in one of the pictures gets a "stereotypical" tabby coat. Also, it likes to insert a horizon, even if the original image doesn't have one, and sometimes it completely changes what's in the background. But I assume this is because of the images in the training set - I guess in coloring books most people have light-colored hair (which can then be colored brown, black, red... whatever) and the model then associates that with stereotypical blondes?

There are several modes (https://portraitart.app/portrait-art) - some of them are better at keeping people looking like they originally look, the "coloring page" mode seems to be the most "heavy-handed"...

It also doesn't like freckles: https://portraitart.app/static/gallery/portrait6_original_10... -> https://portraitart.app/static/gallery/portrait6_pencilsketc...

After some further browsing, the "caricature" mode seems to be the strangest - caricatures are supposed to take the characteristic traits of a person and exaggerate them in a humorous way, while these images sometimes lack even the slightest resemblance to the original. For example, this mixed race couple https://portraitart.app/static/gallery/couple1_original_1024... is not only turned into two brunettes https://portraitart.app/static/gallery/couple1_caricature_10..., but they also have a different pose, different hairstyle and wear completely different clothes...