How to display a preview of a photo in a folder?

Question

Gallery

Tell a newbie how to do it?
There are a large number of folders with photos. It is necessary that when accessing a specific folder using a url like https://domain/img/1111/ (or similar), previews or thumbnails are displayed. At the moment, I haven’t thought of anything better than how to write the Options +Indexes line in .htaccess. In this form, a list of files is displayed and the user has to upload photos without seeing
. Thank you for your help.