CFS: Block images and videos in BING.com using CFS keyword blocking feature
Step 1: Login to the SonicWall Management Interface
Step 2: Goto Security Services | Content Filter
Step 3: Click on Configure button,

Step 4: Click on Custom List tab, In the Keywords Blocking section, click on Add button enter the bing.com/image and bing/videos.
Step 5: Click OK to accept the settings.
Troubleshooting: (If you are using SonicOS Enhanced)
Step 1: Login to the SonicWall Management Interface
Step 2: Goto Security Services | Content Filter
Step 3: Click on Configure button,

Step 4: Click on Policies tab and edit the Default policy. In the pop-up window click on Settings tab and ensure Enable Keyword Blocking is checked.
Step 5: Click OK in the pop-up window to accept the settings.
Testing:
Now the users will be allowed to www.bing.com website and click on Images however when users try to search for images, SonicWall CFS will block it.