We usually store image files in a web accessible directory like this:
App
-assets
-css
-zone_image <<<< image in here
-protected
--views
---customers
----index.php <<<show in this page
You should note that "protected" directory and its sub-directories are NOT web accessible for a security reason, while "assets" and "css" directories are web accessible.
And you have to distinguish the "url" of a file and the "path" of it.
Probably you are trying to show an image with the relative "path" from the view file, but you have to give the "url" of the image file for the img tag.