Below is example of default WYSIWYG editor. CKEditor4 is also the same.
- Go to "Admin" > "Plugins" > "WYSIWYG Editor" options
- Check "Allow images to be uploaded"
- Specify "Maximum size of uploads" size
You can change maximum size with the following PHP settings.
Uploaded images are reduced to 600 pixels. Unfortunately, this resolution has been hard-coded into the editor plugin. If you hope to change resolution, you must hack plugin source (qa-xxxxxxx-upload.php).
Also, if question only, it would be useful my EQF plugin.