Google Images
We've had a few tech support queries about google images recently, and considering the changes google have made to the back-end, I figured it was a good time to try to address the common queries about the google images site.
“Google Images is classified as a proxy site” - This is correct. If you think about the way the site works, it is in fact a proxy site. It displays content from other sites using its own URL.
“I've set up a custom allow for google images, but thumbnails are still blocked” - This is less prevalent since google changed the way thumbnails are handled, but still affects a lot of the thumbnails. The reason is simple – google uses gstatic.com to serve some of the thumbnails, which is (correctly) also classified as an advertising server. If your policy is blocking advertising, you need to add this URL to a custom URL category set to “Allow” in the affected policy.
“The image analyser isn't filtering google images” - This is a tricky one, and one which has two completely different causes. The main issue is the way that google images is serving the images now.
For CensorNet to be able to pass the images to the image analyser, it needs to know that its getting an image. For this, it reads the data stream and picks out the MIME types, then passes the stream to the analyser. Recent changes mean that they are no longer sending that information, instead they are embedding the images using base64 encoding. This means that CensorNet isn't even aware there's an image in the data stream, and therefore is unable to pass the appropriate stream to the image analyser.
The second reason applies only to images that are served the old-fashioned way. Thumbnails often don't contain enough data for the image analyser to perform an accurate scan of the picture, and therefore even though its being passed to the image analyser, it passes through the scan without being flagged.
In short, the only real way to filter google images is to enable the “Safe Search” module in CensorNet, which then enforces the strict search parameter with google itself.
