Search engine optimisation for photography sites is always going to be a problem.

Photographs by their very nature don’t impart much information compared to text.

If we supply as much information as we can about a photograph Google will understand what that photograph is about.

Also following some very simple steps like descriptive Titles, correct document outline, original copy and the natural use of keywords will help make your site at least show up in the SERP (Search Engine Result Pages) for a given keyword/s.
But don’t expect to get to No. 1 in Google SERP overnight.

More SEO Details at my Website

WordPress Image Optimising Plugins

General Tips on Image Optimisation for the Web and WordPress

Yoast

EWWW IO

reSmush.it

WP Retina 2x

Media File Renamer