Maybe she sells authentic, maybe not. There's just no way to tell since the pictures belong to other people.
And authentic seller or not, if she isn't ethical and diligent enough to do her own work, I wouldn't do business with her.
As a seller, it takes me a good hour or more to prepare a listing from start to finish. It involves taking 2 dozen pictures, editing, enhancing, uploading to a hosting site, writing the listing, description, deciding which pictures to use in the listing, etc. Sometimes I have to go back and retake pix if I'm not happy with those that I got. There's tons of work involved and most sellers don't allow others to take the easy "copy and paste" route. (I am aware of one seller who does a lot of business with a Malaysian buyer and she does allow that person to use her pictures on a Malaysian website, but that's the exception rather than the rule.)
If this Singapore seller has permission to use those pictures, perhaps her listings should state that "I purchased these items from the seller whose pictures I've used and I have permission to use them," or something to that effect. But IMO, that doesn't appear to be the case here.
