Image module uses its own temp path

As I see in image.module, the Image modules defines its temp folder inside the image folder.

Personally I would prefer that the temp folder is the one defined in Drupal's settings (returned by file_directory_temp). This way, I can make the image folder available to the public, while I put the temp path outside the htdocs folder (an certainly outside the images folder).

I've attached a diff with the three changes I've made.

Andrei.