Hello, was this topic solved? I have excactly the same problem, with safari it shows ‘?’ instead of the image, in firefox appears no image and no error.
The image axtension is .png.
The entire Folder also to 777.
One little proplem also appears when the site the first time loaded – an error is shown if you click on ‘In den Warenkorb’. If you visit an other site first and go back to the homepage with the logo-link all works fine.