I worked with the default theme as base an am slowly implementing my own theme on top of it by overriding it (as is recommended).
Now, I'm currently trying to install extensions that change how product images are display (my customer wants a zoom functionality as is used on many shops).
I installed them via magento connect without problems and configured them under configuration. Neither shows up on the site. I made sure they're active and are active in the right scope.
I did not override any phtml files so far, only some xml and a lot of css.
I'm using Magento v. 18.104.22.168
I'd be grateful for some help!