The media attachment pages are pages that generate a wordpress page
Noone uses those images today. Noone links to those media attachment pages. Links always point to the real media URLs (like /myimage.jpg and not /myarticle/myimage/)
Those media attachment pages are considered as thin content by Google because they don’t contain any information.
I think that media attachment pages are responsible for drops of organic traffic from Google because there is google penalty related to thin content.
Our case study:
We saw a blog on which the genesis framework & the New pro child theme were installed. After we installed Yoast, we first decided not to redirect media attachment files to the image file. We received an automated email from Google stating the following:
Search Console has identified that your site is affected by 1 new issue of type Coverage.
Top errors (5 maximum)
Errors can prevent your page or feature from appearing in Search results. The following errors were found on your site:
Submitted URL marked ‘noindex’
Yoast added a
Then, we decided to redirect media attachment pages to media file in the Yoast settings.
In the days following this change, Google traffic started to recover. This website had lost most of its traffic for many years. That’s why we think that media attachment pages are really BAD for SEO.