Give a better error when people send a string as an obs photo.
Give a better error when people send a string as an obs photo.

calonso-conabio/inaturalist,inaturalist/inaturalist,inaturalist/inaturalist,calonso-conabio/inaturalist,inaturalist/inaturalist,calonso-conabio/inaturalist,calonso-conabio/inaturalist,pleary/inaturalist,pleary/inaturalist,pleary/inaturalist,inaturalist/inaturalist,inaturalist/inaturalist,calonso-conabio/inaturalist,pleary/inaturalist,pleary/inaturalist