aws-sdk returns object bodies from a plain StringIO, so S3.get handed
back a UTF-8 tagged string and Photo.sniff's binary prefix comparison
raised Encoding::CompatibilityError: "Rebuild resized photos" died on
the first photo with a 500. URL imports had the same flaw via a UTF-8
read buffer. Treat image data as binary at the source and in sniff, and
let one failing photo no longer abort the batch (errors are reported in
the admin flash and logged).
Assisted-by: Claude:opus-5
Sergei Poljanski
61bb1393fe