title: How to add image into a post in django
body: <p>I'm building an blog system, which allow user add image to their blog.</p>
  
  <p>when user add image, the image will be upload automatically, this happened before the blog is posted, so how should I handle the uploaded image, these image is kind  of like temporary image, because if the user post the blog, these images will have an foreign key to this blog , and saved into some folder,but if the user discard the blog , these  temporary images should be deleted.</p>
  
  <p>the problem is how to get the firstly uploaded images,when the blog is actually posted? where should I store these temporary images? and how can I tell if the user discard the blog?</p>