Maximum Image Size - WordPress Plugin
Sometimes, it's not necessary to keep copies of full resolution images on your web server. But, when you solicit images from many sources, you may not be able to rely on users to size images to your specifications. Here's a very simple plugin that removes the full resolution image and replaces it with an image resized to your preference.
The plugin makes no changes to your database and is written with just 17 lines of code.
1) Download the plugin: Maximum Image Size
2) From with in the WordPress Admin Panel, Navigate to Plugins >> Add New >> Upload Plugin. Upload the file you just downloaded in step 1).
3) Activate the plugin.
This plugin has no configuration. It works based on the Large image size, a configuration option which already exists in the WordPress core. You may configure this by navigating to Settings >> Media.
Tip: If you do not wish to retain a Medium image, set both Max Width and Max Height to 0.