preview image broken in WordPress Multisite

I am using WordPress 4.1. Multisite, the plugin works with the main site, but there is a problem with the subsites. If a replace there a file, the file will be replaced, but the image preview in the media library is broken which is not the case in the “main site”. Thanks for your help.

https://ww.wp.xz.cn/plugins/enable-media-replace/