Step 1: Open the PPT and move the mouse to the PPT page.

Step 2: Then right-click and select "Format Background". Open the background format window.

Step 3: Click the picture or texture fill, and then click "Insert".

Step 4: Click "From File".

Step 5: Select a picture to insert into the computer, and the PPT background picture is set.

Step 6: If you need to apply the PPT picture background of the current page to other pages, click "Apply All".