Little known features in Mac OS X's Preview

Wednesday, 13 January, 2016

Talking to my clients, many of them don't know the power of the Preview app in Mac OS X.

To most, they know that when they double-click on a file, usually something opens and let them see the content of the file.

Most wouldn't know that it's called Preview. Fewer, to my surprise, know that you can use Preview without actually launching it.

Here's the trick. After you select a file (or files), press the spacebar.

So you select a text file and press spacebar, a window pops up and shows you the content of the text file.

If you select a photo and press spacebar, a window pops up and shows you the photo.

While the window is there, you have the option to open the file properly with the application associated with that file type.

Or simply press the spacebar again and the window will close.

In the example above, after pressing spacebar, the preview of the picture appears and I have the option to click, in the top right corner, "Open with Preview" (the default action if I double clicked on the file) to open the file or press spacebar to close this window.

What's the use of this?

For one thing, sometimes you are looking for certain files and you are not sure if that's the file you are looking for. It's time consuming if you open each file one by one, e.g. Word documents.

With Preview, you can select multiple documents, press the Spacebar, and one window will pop up and you can use the navigation arrow keys (see above screen shot, in top left) to go from one document to the next. If the document you want is among them, just click the "Open with..." action. If not, press Spacebar again and the window will close.

But wait, there's more!

By the implication of the name, you would think Preview is "preview" only. That's it. Kaput. Finished. Done deal.

What they didn't tell you is you can do also re-size and convert photos to other formats!

Have you encountered the situation where you are trying to upload or send a picture and are told that the file is too big?

Or, more commonly with avatars, you are told that your picture format is not supported?

The first thing that comes to mind, at least to mine, would be "Oh dear, have to start Photoshop...rats!"

Well, before you go out and pay a lot of money for additional software, try Preview!

Changing file format (i.e. from PNG to JPG etc)

First, you double click your picture file.
Click "File" and you should see this drop down menu:
Click "Export" and get this:
Click on "Format" and select the new file format that you want.
Click "Save" and that's it. A new copy of the picture in the new file format is created.

Re-sizing a picture file

From "File", click "Tools" to get the dropdown menu:
Click "Adjust Size" to get this:
You can now adjust the size to whatever you want.
Keep in mind that "autosave" is in place. So if you accidentally close the file, your original file will be re-sized.
I strongly suggest you make a copy of your original before you play with the "Adjust Size" feature.
Sometimes you may have a specific need to have the file in specific dimensions. In this case, click the "lock" icon between "Width" and "Height" to unlock the proportional scaling feature. Alternatively, just un-tick the "Scale proportionally" option.
You can then change the dimensions to specific numbers.

Cropping a picture file

Sometimes it's not good enough to just re-size. You may need to crop the picture.

Open the file.
Move to the cursor to where you want to start selecting your crop area.
Drag to the opposite corner to form a rectangle.
Go to "Tools" and select "Crop"
And you get the finished product:
Close the file and it's automatically saved, or export (see above) to another file format.