Search within theme is not working

Hi, I’ve got two wordpress sites with the exact same problem. I was hoping someone on this list could help me out.

I’m a cartoonist, and my posts are pictures, not text. However, I would still like my cartoons to be searchable within my site. For this reason, I’ve given every one of my posts several descriptive “tags” so they can be searched for, by keyword.

Here are my sites:
https://www.mixedmedications.com
https://www.amazingcarlos.com

Here’s my problem: If I enter a word into the search field on my site, I always get the message back – “No posts found. Try a different search?” But the descriptive word I am entering is a “tag” on a post. WordPress is ignoring my tags. How come? Why don’t my tags register in the search?

Again, these are cartoon sites, and there is no “text” in my posts, only images, so “tags” are the only means by which I can organize my data. Is there a way to get wordpress to include my tags in its search?

Any help would be greatly appreciated.