I'm Ava from Shopify Support, I'd like to help you here.
One reason these images are showing as greyed out is if there is no stock added for these particular products. Have you gone to the product in the admin and added stock? There is a guide here on how to update your inventory!
Also, can I ask if you have made any coding changes to your theme? Just so I have some extra context.
Social Care | help.shopify.com
can you please provide your site url and if any password then provide password so that i can check and provide solution