Changing the size of images ignored by Image Analyzer evaluation

This article applies to:

• Trustwave MailMarshal (SEG)
• Image Analyzer functionality

Question:

• How can I adjust the setting for small images ignored by Image Analyzer?

Information:

Current versions of MailMarshal limit which images are submitted to Image Analyzer. By default, images smaller than 75x75 pixels are not submitted.

This limitation helps to speed processing and avoid false positive returns from common small images such as corporate logos.

You can configure the size of ignored images using Registry settings.

• Note: If EITHER of the conditions is met then the image will not be submitted. For instance by default an image 70x76 pixels would not be submitted.

• In MailMarshal 10.0 and above, open the Management Console and navigate to Advanced Settings. Edit one or both of these existing values (or add the entry if it is not present):
  • Name: Engine.ImageAnalyzerMinWidth
  • Type: Integer
  • Value: Minimum width in pixels of images to submit to Image Analyzer. Images with a smaller width will not be submitted. Default: 75. 
  • Name: Engine.ImageAnalyzerMinHeight
    • Type: Integer
    • Value: Minimum height in pixels of images to submit to Image Analyzer. Images with a smaller width will not be submitted. Default: 75. 
• In MailMarshal 8.X and below, open the Registry Editor on the Array Manager. Within the base registry key, navigate to \Default\Sender
  • In version 8.X: HKEY_LOCAL_MACHINE\SOFTWARE\Trustwave\Secure Email Gateway\Default\Sender
  • For information about the registry location for each version, see article Q10832.
  • Edit (or add if necessary) one or both of the following values. Use Decimal entry to avoid confusion.
  • Name: ImageAnalyzerMinWidth
    • Type: DWORD
    • Value: Minimum width in pixels of images to submit to Image Analyzer. Images with a smaller width will not be submitted. Default: 75. 
  • Name: ImageAnalyzerMinHeight
    • Type: DWORD
    • Value: Minimum height in pixels of images to submit to Image Analyzer. Images with a smaller width will not be submitted. Default: 75. 
• Save your registry settings or configuration settings.
• Commit the configuration changes and restart the MailMarshal Engine service on each node.

As always, take due care when editing the Registry. Trustwave recommends that you make a backup before applying any changes.