Overlay Text Block on Gallery Section Image?

I added a Gallery section to my homepage that has a single image that is clickable. I want to add a text box overlaying the image but don't see any options to do so. Any suggestions?

Hello,

If you could attach a link to your website, we can see the context of how you want this to function and hopefully provide a solution.

Thanks,

Dan

This answer is from an older thread but I think it should still work for you. It will not work for any gallery block that doesn't have lightbox option, like a crousel slideshow. 

Yep, you can do this with some Custom CSS. On your  page where the Gallery is, go to each image and enter the "bio" text into the Title/Description fields for each image. [edit] You must also enable "Lightbox" in the Gallery's Design Tab! 

Under that page's SETTINGS pane, go to the Advanced Tab and add this code to the "Page Header Code Injection 

<style>
div.sqs-lightbox-meta {
 background-color: rgba(255, 255, 255, 0.500);
 height: 90%;
 padding: 50px !important;
}
.yui3-lightbox2 .sqs-lightbox-meta {
 opacity: 100;
 color: #000;
 font-size: 40px;
}
</style>