Can you authenticate a card from photos?
In short: Often, but not always. I give an opinion with the checks the photographs allow, state that no physical inspection was performed, and say when the images are not enough.
Photographs and a short video under a light can show print pattern, font, colour and holo. They cannot show weight, thickness or the light test, so those checks are marked as not performed.
If your photos are not good enough, I ask for better ones before I start, at no charge. This also works for pre-purchase second opinions from a listing link and the seller's photos. Images you send are kept under the retention and consent policy.