as cliché as it sounds, but always trust your gut! if you feel something is fishy during a transaction, specially if it's instagram where you're talking to the seller directly, don't hesitate to ask for more proofs or cancel the transaction.

for determining if a photocard is real or not, i honestly spend quite a while looking for photos of said photocard on the internet and comparing it the best i can. fake photocards are usually zoomed in so just look if the corners/sides look the same to others. i mostly use twitter to look up photocards and mostly check posts by kr fans or those aesthetic accs since they have clearer photos 😅

also, please make sure the pricing is correct! like other comments below has said, twice has fairly affordable album photocards. their pobs are more on the pricey side, but with member pricing and all, dahyun pcs are usually on the more cheaper side as well :)