The scan in DS Recovery looks at the whole phone, not only at deleted files. That is why the results can include pictures that are still on your phone.

What you may see

Thumbnails: small preview copies that the gallery and other apps create.
Cached images from apps such as browsers and messengers.
Copies of photos that are still in your gallery.

How to find the deleted photos faster

Sort or filter the results by date and look around the day you lost the photos.
Use the preview: a small, blurry picture is usually a thumbnail – it can still be worth restoring if the original is gone.
Keep scrolling: the scan shows results as it finds them.

Tip: if a photo you need appears only as a small thumbnail, restore it anyway. A thumbnail is often the only copy left once the original has been overwritten.