That's an interesting website, thanks for posting! They are not PECS though. PECS is a specific set of pictures- the idea being that the pictures are universal (that's also apparently the idea behind the Noun Project, but PECS are generally used in sp.ed. settings universally). I think these might be better than PECS for some kids though, because they are simpler pictures.
Anyway, I thought I'd add SET-BC to this thread because they have a good resource for free PECS if anyone's thinking about starting to use them. https://w3.setbc.org/students/Pages/PictureSET.aspx
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Mum to two awesome kids on the spectrum (16 and 13 years old).