To show display images of Items in search, the ‘Web Store‘ feature needs to be enabled on Netsuite.
To enable the Web Store feature, navigate to Setup > Company > Enable Features > Web Presence tab > Web Site section.
This will provide you two fields in searches Store Display Image and Store Display Thumbnail fields which help to display images of items on saved searches.
Note: Using the Formula(text) field to pull up the Store Display Image and Store Display Thumbnail fields, will return ERROR: Field Not Found if the Web Store feature is not enabled.