You might want to consider implementing a flip icon (that looks like a corner folded) in the lower right corner of the cards which causes the cards to flip on each click and during hover flip temporarily for the duration of the hover.
If you hover over the card, you can see the other side, then see the previous side when you move the mouse off it.
If you can not hover over the card e.g. because you are using a touch screen, you can click on the corner fold icon to see the other side, then click on it again to go back.
This ensures that both mouse and touch screen users can enjoy a similar experience and the fold symbol on the corner helps hovering users realize what is going to happen/has happened so they won't be surprised by the hover flipping the card.
The site should pre-load the flipped sides (e.g. include them in HTML as hidden), both to prevent delays on click/hover and to not break SEO.
Take into account that if the card was flipped by a click on the corner, then hovering over it should flip it back during the duration of the hover.
Also, you might want to consider adding show all as images, show all as info, show all as both (both sides, side by side). The first two enable the users to reset all to the same state (either images or info) and the second to see both sides at once (thus showing half as much cards per row - double the rows).