Tools: Resize Item Images
A space saving feature is the Resize Item Images
tool found at:
ACP -> MODULES -> CORE -> IMAGE SUPPORT -> TOOLS -> Resize Item Images
This tool allows the admin user to shrink the size of existing images on the server down to a maximum size.
If your users have uploaded gigantic images, these images will probably never be seen because smaller more optimized images will be created from the original.
You can use the Resize Item Images tool to reduce the large images down to a reasonable size to save space on your server.