Sean Butze

Many users do not compress or resize their images before uploading them into a post, and oftentimes WordPress’s maximum upload limit of 2MB-10MB is still too large to prevent the insertion of photos that can signficantly slow down a website.
WP Image Size Limit allows an administrator to set a custom file size limit that is specific to image files and smaller than WordPress’s general file size limit.
This is especially useful when you need to put tighter restriction on image uploads but want to preserve the ability to upload larger files of other formats (audio, video, etc.).

WP Image Size Limit

Just what I needed to tamp down those designers who think it's okay to use 20MB images!

Brilliant

Adds a new setting under Settings -> Media where an admin can set a maximum upload file size for image files.

Dion Hulse

This plugin offers limited support. Please do not expect new features or too many bugfixes. Features may be removed at any time.
Add From Server is designed to help ease the pain of bad web hosts, allowing you to upload files via FTP or SSH and later import them into WordPress.
This plugin is NOT designed to.. 
 * Be used as a replacement for the file uploader 
 * Be used for migration of websites 
 * Re-import your files after moving webhosting 
 * Batch import media
This plugins IS designed to.. 
 * Import files which are larger than your hosting allows to be uploaded. 
 * Import files which are too large for your internet connections upload speed.
WordPress does a better job of file uploads than this plugin, so please consider your needs before you use it.
You may also want to look at using WP-CLI for media import purposes: 
https://developer.wordpress.org/cli/commands/media/import/

Add From Server

Whenever I need to upload media files that are too big to upload directly to WordPress, I FTP them to the server and use this plugin to add them.

Great tool for those big media files you can only ftp to the server

Add From Server is designed to help ease the pain of bad web hosts, allowing you to upload files via FTP or SSH and later import them into WordPress.

WP Image Size Limit vs Add From Server