Looks that shop thumbnails images are missing http://prntscr.com/q54e47
Try to regenerate thumbnails. Actually, your site (backend and frontend) is so slow for us that we can’t even open single product or product categories from backend. You keep enabled 89 plugins, OMG. Check the plugins list and disable those you don’t really use, hope you know that every additional plugin slows down site and takes server resources.
Hello, I deleted the useless plugins but the problem of displaying images persists. This problem is due to the fact that my web server is not powerful enough or the images are poorly sized? Could you import an image to check and give me your opinion? Please, thank you.
Point is that file exists in that folder, for example, http://prntscr.com/q5nsri
So, contact your hosting provider to find out why it displays 404 for the files.
Also, one of your plugins causes fatal error http://prntscr.com/q5nyh9
Contact plugin author.