Actually working on trying to optimice ALT and TITLE tags for SEO, but detected that there were lots of unused images on WordPress media library.
So sounded smart to clean it up first, then found that was not easy task to know which of them were in use.
Keep working on it, I’ll update later.
[ update ] trying “Image Cleanup” plugin, remember doing a backup first. Also deactivate all the cache systems. Works fine, at least, does not breaks a thing. Should check now the size of my customers site, to see if its effectively deleted.
[ update ] checked, it really deletes and cleans unused images, ended up from 98 to 91Mb.