What I need seems kind of simple. I am surprised I haven't found an answer on here yet.

I want to have the sliders on the main page act as a direct link to a menu item. So, basically, I want to have the "IMAGE" act as a link. The problem is, since this isn't in the actual content, but in the image tag, I don't really see how to do this.

Any thoughts?

What kind of module are these sliders?
If they are K2 Content modules you can use a text extrafield to act as a custom link. There are several threads on how to render specific extrafields in this forum.

I'm not familiar with the extrafield and I haven't found any straight-forward relevant topics. I created an extra field in a new group called "Link URLs". When I go to the K2 item and choose the extrafield tab, it tells me I have to first select a category to see related extra fields. But I have no idea where I am supposed to do that - I don't see an option.

You can find a comprehensive guide here: getk2.org/documentation/k2class2012

Extending K2 Through Plugins Part 1 and Part 2.

As for the code there are several examples in the forum.