What’s the best way to rank a background gallery website?

I own a network of 5 different sub-websites (same main domain, different parts of the site. /1/,/2/, ect)

There isn't any text posts or hardly any text if any at all on the entire site. I have a header with my logo then a footer with some social icons. The only text on the page is the "Load more" button to generate more images.

From my brief knowledge, I understand that a key point when it comes to keywords is actually having words on your website.

Basically, my question is, am I out of…

What's the best way to rank a background gallery website?