You can use an import to upload multiple images and this article shows you how: Import Images.
Live App Import
If you want your users to be able to import multiple images into a single image field, you'll need to change your app structure a bit. For example, you want realtors to submit multiple photos for each new home listing.
An image field can only store a single image, so you'll need a connected object to store multiple images for a single record. This article shows you how to set that up: Store Multiple Images or Files for Individual Records.