Follow the steps below to upload a footer background image:
On the frontend, in the Admin bar, Customize.
On the backend, click Appearance » Customize.
Navigate to Footer » Settings section.
Locate the Footer Image call-out.
Click the Select image button to open the WordPress media library.
To upload the footer image file, click the Upload Files tab in the upper left corner of the Select image dialog box.
You can drag and drop any image file from your local computer or machine’s file manager, or you can click Upload Files to upload the footer image file.
In the File Upload dialog box, navigate to the location of the image you want to use, and then double-click the image to upload it.
Once the file uploaded, the Media Library tab appears with the uploaded file selected.
At the right side of the Medial Library, complete the Title, Caption, Alt Text, and Description text boxes, and then click Select button.
The Crop Image dialog box appears.
Use the sizing handles to select any portion of the uploaded image you wish to be displayed as the site logo area, and then click Crop Image button. Suggested image dimensions: 1920 by 286 pixels.
Now that you have a Background Image, you will see the available options:
Background repeat – Specify if/how the footer background image will be repeated.
No repeat – The background-image is not repeated.
Tile – The background image is repeated both vertically and horizontally.
Tile horizontally – The background image is repeated only horizontally.
Tile vertically – The background image is repeated only vertically.
Background size – Specify the size of the footer background image.
Default – The background image is displayed in its original size.
Cover – Resize the background image to cover the entire container.
Contain – Resize the background image to make sure the image is fully visible.
Background position – Specify the starting position of the footer background image.
Click the Publish button to view the uploaded footer image on your site.