Step 1 : From the website setup record verify the correct naming format of the image .
For example,
Step 2 : Verify the correct folder, that image is to be uploaded.It will be getting from image folder field in the website setup record.
Step 3:
To attach an image to an item:
Go to Lists > Accounting > Items.
Click Edit on the item record
Go to the Web Store subtab.
Search for and select the desired images in the Item Display Image field and Item Display Thumbnail field.
Click Save
Step 4 : It is a note , when we uploading the images into the file cabinet folders it also uploaded in the associated image field in item record. This field will act as a link between Netsuite side and website.