Where can I find where this content is being loaded from? Helping out a friend with a Drupal based site. On one page, he has a series of images with a lightbox displaying info once clicked.

This however doesn't function, and instead shows as an image title.

I was just wondering where I'd find the file with the descriptions?

Thanks
That's not a simple question, it depends on the site. For your case you will first want to check Nodes (Content items) as that could be a WYSIWYG field. Otherwise if it's hard-coded it would most likely be in the theme folder that's currently enabled.

You can also check Views for the page that's showing all of them as a series of images. That could give you information on what type of Content they are.