This is a problem that may arise oif you upload images to your image folder. The default configuration of Joomla sets the path to the image folder to images/stories. If you upload your images outside the stories folder you won't be able to access them from the editor.
To solve the problem, you have two options:
- Upload your images to the images/stories folder or a folder inside this folder
- Change the Global Configuration of Joomla so that the Path to Image Folder is set to images and not images/stories
You can do this by going to Global Configuration, System and then edit the Media Settings. Change the Path to Image Folder to images only.