I looked in settings/override/image.ini.append.php and all the data stored are the same that i find via terminal (path is correct).
I have this problem only on preview images in media/images and not, for example, for logo image on my home page or on background image (stored in css files).
But if I try to create a media/image or simply i try to paste an image on an article, image don't appear yet.
Does this also occur in the admin interface ? If not, this could just be a policy issue (anonymous user might not have right to read content objects from the Media section).
Moreover, it is not possible to paste an image on an article. You need to use the image button in the rich text editor.