Photos is not an app that goes through all your Finder folders to find your pictures. I'm not sure that such an app exists. You can use Finder to search for all files with a jpg suffix, or even all image files. And you can use QuickLook to view them.
View and edit files with Quick Look on Mac - Apple Support
Rather, Photos is an app that helps you organize your pictures, and it offers non-destructive editing of those images. We import our pictures to Photos, and they are stored in the Photos Library that's located in the Pictures folder. Most experienced users also move those pictures that had been in Finder folders to an external drive for backup-- so there is a picture in Photos' Library and also on an external drive that's put safely away.
We also may have pictures in Finder folders that we don't import to Photos-- lots of icons and app associated images, temporary edits, screenshots, and so on, that we may not want included with our photographs. The app Preview can be used to view and edit these stray pictures.
Once pictures are in the Photos Library, we can use Photos to organize them by putting them into Albums, adding keywords, putting comments into Captions, and so on. This is made easier, because pictures have different attributes from other files. Pictures have pixel resolution, object names, face ID, location, etc, that Photos can use to search and identify.
Photos is an app that does for pictures what Finder does for other files. Pictures can be imported to the Photos Library using the menu choice File>Import. There's more information here:
Get started with Photos on Mac - Apple Support
