It happens in WordPress multi author blogs that your users do not compress or resize their image files before inserting them in their blog post, and oftentimes WordPress’s maximum upload limit of 2MB-10MB is still too large to prevent these image insertion which can signficantly slow down your WordPress site.
The article is on a simple WordPress plugin called WP Image Size Limit which lets WP site administrators to set a custom file upload size limit and this becomes specific to image files and smaller than WordPress’s general file size limit.
You can set the limit in Media panel under Settings menu:
WordPress media uploader displays both limits:
The plugin is especially useful when you need to add tight image upload restriction but want to preserve ability to upload larger files of other formats like audio files, video files, etc.