Magento uses temporary images as placeholders until the permanent product images become available. A different placeholder can be uploaded for each role. The initial placeholder image is the Magento logo, which you can replace with an image of your choice.
To upload placeholder images:
On the Admin sidebar, tap Stores. Then under Settings, choose Configuration.
In the panel on the left under Catalog, and choose Catalog.
Expand the Product Image Placeholders section.
For each image role, tap Choose File . Find the image on your computer and upload the file. You can use the same image for all three roles, or upload a different placeholder image for each role.
When complete, tap Save .