How to change or add an images

From the layout page, you will find a new widget called "Broken Images Replacement". Click on edit.

You will find a list of the brand names, each brand name has an image that will appear if a post URL contains that brand name. You can delete or edit any of them. The generic image is the last one on the list.

If you click on edit, you can easily change the name of the brand or the URL of its image.

You can easily add a new brand. see the image.

You should upload the images on blogger, open a new post and upload your images then right click on each image and choose "copy image address" to get the URL.