cant simply browse picture files from external storage

Another Finder option to browse a folder of images is the gallery view. If you open a folder of images and set it to Gallery view, you will see one image enlarged and the other images as a filmstrip below the enlarged photo. And the panel to the right will show you the metadata of the photo. You can use the arrow keys to step the gallery or the trackpad to swipe between the images in the film strip:

Of course there is. You can do it simply in the finder, with Quicklook - select one of a folder of images and tap the space bar. Move to the next images using the up/down arrows. Plus there are many many simple file viewers, from Preview (already on your Mac) to quite a few on the Mac App Store and from trusted developers. Personally, I really like Graphic Converter for the job.

You weren't spoiled by Windows. All that's happening is you're expecting your Mac to be the same. It can do the same things but there is a learning curve as you transition.