Magento image upload error "destination folder is not writable or does not exists"
Magento image upload error occurs in most of times after moving the files from one hosting to another.
In this case the folder permmisions were changed and the magento code is unable to upload the image or to create a new folder in his destination folder.
Destination folder is this one: media/tmp/catalog/product .
The solution for this is to use winscp or something else that allows you to change file permission to 777 recursively.
Now you are able to debug your code.