I tried to enable the Imageproxy, but unfortunately it doesn't work for me. Activating the private key feature doesn't help, and if I try to access an image manually through the proxy.php the only output is this:
How can I debug this feature and what do I have to consider when I enable it? The link proxy and all the other new features work fine so far.
Enter the number of days that proxied images should be retained before they are removed from your system. If the image is re-requested after this time, it will automatically be fetched again. Use 0 to retain the images indefinitely.