I have tried to specify the maxium image dimensions in Media Settings for all image sizes:
Thumbnail 150x150
Medium 300x300
Large 400x400
However whenever I insert a larger image into my posts/pages they are not automatically downsized (I normally add Media Files from URL). The original HUGE image is posted.
Have I misunderstood what these settings do? Do these settings not limit the size of dimensions in your blog?
If not, how do I do this please?