Previous photos in lightroom

> How comes that my “old”/previously edited photo is still present in my lightroom? When I have imported my new photos I can still see my previous photos. 

I don’t know what you are asking but I think you may be using a uncoinventional workflow.   Let’s say you import image “V1” and edit it.   Then what do you do?  If you “Export” the image creating image V2 and then tomorrow come back to LrC and Import image V2 then you are not using LrC correctly as you will have a whole seires of image in various states.   

Assuming that is similar to what you are doing, do this instead.   Ather editing V1, just close LrC.  Tomorrow your edited version of V1 will still be there ready for more work - you don’t have to do an export to save your edits.  If you ever want to go back to a prior edit state (say from last week) you can do that using the History Panel in the develop module.  

If my presumption of what you are doing is incoorect, please explain your workflow in more detail.

If you only wish to see a specific new selection of images, and do not wish to see anything else, you might wish to check out Adobe Bridge. If you download a group of images into a folder, and select that folder in Bridge, all you see are those images.

For enhancing images, you’ll need Photoshop. When you have Photoshop installed, it will also install the plugin of Adobe Camera Raw. Enhancing an image in Adobe Camera Raw is (mostly) identical to working in Lightroom. (Lightroom Classic is Adobe Camera Raw with a database.)

Also, as ​@dj_paige aludes to, if you place all of your new images into a folder, all you will see in Lightroom Classic are the images in that folder. As you move from one folder to another, you will ONLY see the images in that folder.

The primary difference then between LRC and Bridge is that ALL of your images are readily available in LRC, while Bridge does not keep any collection of your images, you just open the folder you wish to look at in the Finder or Explorer and look (and work) at them with Bridge, ACR, and Photoshop.

Actually, what you are seeing is the way Lightroom Classic is designed. All of your photos (current and previous) are shown in the Lightroom Classic Library module when All Photographs is selected on the left under Catalog.

You can just view the current import, on the left of the Library Module under Catalog, there is an item that says “Previous Import”, click on that. There are other ways to limit the photos shown in the Library Module, such as selecting the folder that the photos are in, or filtering by capture date, and probably other methods as well.