Are you using the Import on the admin Product List page?
Have you checked the
System > Log after the import to see if any error messages?
Note that the drive where the import pictures are present must be accessible to the application.
First do a small Export of product with a picture. Note the drive letter/path of the picture. Use that as a
basis of where the new import pictures should be, but don't use that specific path.
For example, if you Export one product (selected) from the admin demo
https://admin-demo.nopcommerce.com/Admin/Product/List, you would see this path
C:\web\admin-demo.nopcommerce.com\wwwroot\images\thumbs\...
So, you could create a new temporary folder
C:\web\admin-demo.nopcommerce.com\wwwroot\
newimagesAnd then put your pictures in that folder, and use that path for the Picture1, Picture2, etc. in the .xlsx file.