Implementing Post Icons on vBulletin 
The administrator can choose to enable or disable Post Icons for at the forum level and can also choose which Post Icons can be used by which usergroups if Post Icons are enabled.

To enable Post Icons on your bulletin board you need to edit the forum permissions for each forum that you wish to allow Post Icons. Forums & Moderators > Forum Manager > Edit Forum > Enable/Disable Features

Set Allow Post Icons to Yes. Repeat these steps for each forum.

The administrator can also choose to enable or disable Post Icons in Private Messages too. vBulletin Options > Private Messaging Options > Allow Message Icons for Private Messages

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