change the image source to an actual image

Author: dks333

content/components/cards.mdx

@@ -38,7 +38,7 @@ Add a `horizontal` property to a card to make it horizontally displayed.
 
 Add an `img` property to a card to display an image on the top of the card.
 
-<Card title="Image Card" img="/images/card-with-image.png">
+<Card title="Image Card" img="https://mintlify-assets.b-cdn.net/hero-light.png">
   Here is an example of a card with an image
 </Card>