How do I change the automatic image resize values

1. Click on main menu item Customise
2. Then click on Global Settings
3. Find heading Image Resize Values
4. Here you can edit the automatic image resize values
5. You can edit the maximum upload width of the image (original setting 1000)
6. The maximum view image width, which is the image that pops up in a light box (original setting 500)
7. And the maximum thumbnail image width, which is the small image shown in a gallery (original setting 100)
8. Save Changes