When you need to update or change the image on your products you should go to Main Menu > Products look for the item and edit to change the image
Main menu > Products
Look fo ritem and select
Touch the image to select the options given - save and sync the device
You may also update or change the image on products from the web version web.selbuk.com
Database > Products > View/Edit
select or look for the product
Click on the image to select the option.
If you need to update an image first delete the one you have. Then click on update to look for the image on your download folder, select and then submit once you see the new image save