Hi Cristina, thank you so much for your reply but I am afraid I'm not sure what you mean? I don't know how to check if the attachment URLs had visits from bots. The latest thing is google has sent me 410 errors (they are all related to my images) say that they cannot crawl them.
Yoast has told me this:
"Google Search Console may notify you of an increase in crawl errors after changing the setting. This is to be expected when a large quantity of previously indexable URLs suddenly returns 301 redirect status codes. You do not have to do anything and Google will eventually drop the attachment URLs from the search results since they don't exist anymore.
If you continue to see the errors, you can speed up the process of Google removing attachment pages from your search results by installing and activating the Yoast SEO: Search Index Purge plugin. This plugin makes all of your website's attachment URLs return a 410 deleted status as well as redirecting them to the media files.
After six months the attachment URLs (410 crawl errors) should be gone from the search results. At that time, you should remove the search index purge plugin and keep the redirect setting of the attachment URLs set to “Yes”."
I am confused as to what to do. I don't want to wait six months for this to sort itself out! I have asked other friends with blogs and they say they don't know whether their images are set to yes or no for redirect.
To make things worse a website developer has just told me that because of the redirects my site is super slow...
I'm sorry if I sound as though I don't know what I'm talking about, I'm just a little confused and don't know what to do for the best of my site.
Thank you Cristina, your help is so very much appreciated.