I thought that the Preview app on the Mac is great at its job, which is viewing files (as opposed to editing them). But I recently found otherwise.
I have a folder full of photos that I wanted to see a full-screen slideshow of. But Preview can’t do this. You can’t open a folder in Preview. As a fill-in, you can select all the files and press Cmd-down arrow to open them. But this opens other files in the respective apps, opens one Finder window for each subfolder, and gives you a warning dialog saying that there’s no app installed that can open Thumbs.db. This is irritating.
OS X should have folder associations in addition to file associations — apps that want to support opening a folder can register, and you should be able to right-click on a folder and choose Open In > Preview or other app.
In any case, once you open the image you want in Preview, and full-screen it, you can’t zoom in to a photo. This matters for high-resolution photos and panoramas, which are appreciated in their entirety by zooming in. Zooming also helps if you want to take a close look at an interesting part of a photo, even if its resolution is less than that of the screen’s. Unfortunately, Preview doesn’t let you zoom in full-screen mode.
If the photo’s aspect ratio is different from that of the monitor, you get black bars on the left and right sides. This reduces the screen space available for the photo, on laptop screens that are small to begin with, preventing you from fully appreciating the photo. To fix this, Preview should have a Fill mode that scales the image up till the black bars disappear, even if the sides of the photo clip. Pressing Cmd-Plus in the normal mode should take you to the Fill mode. And pressing Cmd-Minus should take you back.
When you open a file, Preview often doesn’t open maximised. It instead opens the photo in a smaller-sized window, at 100% size. If the image’s resolution is less than that of the screen, like 1024x768, the photo takes up only part of the screen. This prevents you from fully appreciating the photo, and requires you to take an extra step to maximise the window. Which you need to redo when you close the window and open a new one. This is a general problem with OS X, but it’s more irritating for photos, which don’t really have a natural size they should be viewed at (leaving aside implementation details like the pixel count).
If you want to pan around a zoomed image, older versions of Preview conveniently let you hold the mouse button down and drag. Unfortunately, Apple got rid of this feature, and the hand cursor that let you do this. Dragging now draws a rectangle to select an area of the photo. This is useful for editing, not for viewing. Sacrificing viewing for editing is the wrong priority for a viewer app. Preview shouldn’t lose track of its raison d'être — a viewer should prioritise viewing above all else.
Finally, while you’re seeing your photos, you can’t easily delete ones you don’t like by pressing the Delete button on the keyboard.
All these in aggregate result in a poor photo viewing experience on OS X. Windows did a better job a decade back, albeit a third-party app. Hasn’t progress been made in a decade? Why are common actions still so convoluted?