They are usually expensive, have naff pictures and allow no flexibility about whether you have the words on the front or rear or not, but this is about something less obvious.

It took me years to notice this, but students who can identify the correct card every time fairly often still can’t come up with the same word in storybooks, real communication, etc. This is generally true for language learning, especially with young learners and even when learning L1 – and is one of many reasons for introducing alternative ways of approaching the language like stories and real communication as soon as possible. You can also, however, do something with the flashcards. Simply use several pictures for each of the words you are trying to present, e.g. a photo of a cat on one flashcard, a realistic line drawing of a cat on another and a funnier figure of a cat on yet another. This can be done by using the ClipArt from the Microsoft Office website function in Word in very little more time than it would take to make a pack of cards with just one picture for one word (maybe 30% more time in total).