This article explains how to upload multiple photos to Facebook at once using a web browser or the Facebook app.
How to Post Multiple Photos in One Post on Facebook 2023
There are two ways to upload more than one photo to Facebook from a web browser. One is through a normal status update and the other method is to create an album. You have complete control over who sees the photos you upload.
Want to add a status update at the same time you post new photos? Here's how:
Select Photo/Video under the status field.