How to update image in gridview

Question

I am developing asp.net app.

I tried "http://www.c-sharpcorner.com/UploadFile/9f0ae2/gridview-edit-delete-and-update-in-Asp-Net/" link for edit and update.

Link is working properly.

But in my code I am using image. grid view contains 3 columns name address and photo.

The link code is working properly for edit and update text.

But I can not update photo.

Can any one  explain me how to update photo?