The Clearswift Gateway detects and blocks images classified as unacceptable within messages. An unacceptable image is defined as either:
- An image that has been manually classified as unacceptable.
- An image that has been automatically classified by ImageLogic as unacceptable due to similarities with nude or pornographic images.
Detecting Unacceptable Images
You can detect unacceptable images by adding a 'Detect Unacceptable Images' content rule to a policy route.
ImageLogic scans and classifies each image, rating it with an acceptability score. Unacceptable images can then be processed (typically quarantined) by the Detect Unacceptable Images content rule. Within this content rule, the sensitivity of ImageLogic can be adjusted by defining a threshold value for acceptable images, or reverting to the system default threshold value.
Classifying Images
You can manually classify specific images as either acceptable or unacceptable and ImageLogic will use those classifications when those images are encountered within messages. A single image or a ZIP file containing several images can be uploaded and each of the images can then be marked as either Acceptable or Unacceptable. If an image is already classified, the existing classification will be displayed but this can be changed, if required. Supported image formats for uploading are jpeg, png, bmp and gif. See Uploading images to ImageLogic for more information.
If an image has been incorrectly categorized as unacceptable by ImageLogic, you can manually reclassify the image as acceptable and reprocess the message. See Analyze and manage held messages for more information.
Access Permissions
The administrator can control which users can view the images in a quarantined message by assigning privileges to view the Image tab when viewing a quarantined message in the Unacceptable Images Message Area. The administrator can control which other administrators can fine tune ImageLogic by assigning the 'Classify Images' privilege. See Creating a New User Account and Modifying an Account's Details for more information.
Peered Gateways
Image classifications can be used by all peered Gateways and, when an image is reclassified, the change will be sent to all peers in a peer group. Copying this information may take several minutes. See Replicating ImageLogic classification data to peers for more information.
Resetting Classification Data
You can reset ImageLogic classification data which will remove all of the currently held data on the current peer. See Resetting ImageLogic classification data for more information.
Backing Up Classification Data
ImageLogic classification data can be backed up by selecting the Configuration System Area when performing a System Backup. See Backing Up the System for more information.
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The detection of unacceptable images is not guaranteed. Although the technology is constantly improving, it is a very complex subject and, therefore, the feature may generate occasional false positives. As with each content analysis feature, deploying ImageLogic will incur additional processing overhead, so consideration to the specification of the hardware and message volumes is important. Images in a Zip file may be in directories but not in a nested Zip. Zip (including *.zipx) is the only supported archive for uploading images. Image Classifications will be applied automatically; you do not need to apply the configuration for changes to take effect. |