I have set the image paths.

When I open the image browser to add an image I cannot see the images from another user. That is OK.

 

But when I know the name of the file and the directory name from an other users image

  I can still add an image from the path of another user.

 

In you example I can add this in Tim's editor and that shows the image. <img alt="" src="http://cutesoft.net/Uploads/Users/Mary/001.jpg" width="1024" height="768" />

 I am affraid that we cannot stop this.