View product photo in the Gridview and update it by uploading a new photo.
- edit the product table (add the product photo)
- edit the related procedure (updateproduct)
- edit the related functions (updateproduct)
- customize the Gridview to view the photo, and view uploadfile control when update photo.
- customize the code behind to view the photo, update it, and save the photo in the image folder when updating a product.