Withyou get a and a fully functional Finder. Let's take a look at Finder's new bag of tricks.
Gallery view replaces Cover Flow. Like Cover Flow, you get a large preview of the selected file, but the preview is even larger with the gallery view. Unlike Cover Flow, it shows small thumbnails below the preview instead of the awkward list view that Cover Flow displays at the bottom of the Finder.
It's easier to scroll sideways through the small thumbnails in the gallery view than to scroll vertically in the list view in Cover Flow because only a few lines could be displayed unless the preview image was really small. The gallery view uses the place of the finder better.
You get the same navigation bar on the left edge of the Finder, but the right edge displays helpful metadata for the selected file when you are in the gallery view. (You also get metadata in Column view.)
You can hide the metadata – you may find it more useful for photos than for Word documents, PDFs, and other file types – by going to View> Hide Preview . However, hiding the metadata area does not increase the size of the preview image.
I saved the best for last. You no longer need to open the preview to comment or rotate a picture. Mojave provides Preview's drawing tools along with the helpful knob in the Finder. When you select an image file, three buttons appear at the bottom of the metadata preview area: Rotate Left, Markup, and More.
Turning Left is self-explanatory, but you can hold down the Option key to turn right.
Markup opens the image in a preview window (but not with preview) where you can paint on the image, add text or arrows, etc. When you're done marking your photo, you can do it Save as a new file or replace the original. For video files, the Markup button becomes a Trim button that allows you to crop start and end points of a video. If you select multiple photos, the markup button becomes a Create PDF button that allows you to transfer multiple images into a single PDF file.
The More button lets you create a PDF file of an image file, and there is a Customize button where you can add your own selections to the More menu.
For more, here's everything you need to know about MacOS Mojave.