It turned out that 30 of the installed plugins, 2 "conflicts", which when uploading new images, clip art, HTTP error and error Internal Server Error. One of the plugins was Regenerate Thumbnails. It is due to these čërtovyh plugins are not loaded image on the site.
So out of this situation: deactivate all plugins, find conflicting and deactivate it. You can deactivate a plugin, then 3 check-image upload. Cheers, I have everything working.
Read more here https://chempalov.ru/?p=17226