Disable image thumbnail link in blog post

Site URL: https://www.bosco-andrew.com/hosp1

I would like to disable the link in a thumbnail image post. I have read posts that mention to use the code below but it is not clear where am I supposed to place this code exactly.

Thank you for explaining this to me as if I was a three year old.

.summary-item a {
   pointer-events: none;
}

4 hours ago, BoscoH said:

I would like to disable the link in a thumbnail image post.

I'm not sure which link you want to disable. Can you post a screenshot of the image or describe in more detail so we know which one?