Preview

From EPS to PDF in No Time Flat:
This trick is pretty much just for graphic designers who work with EPS images from applications like Adobe illustrator, Coreldraw for Mac, Freehand, and Photoshop.
If you want to convert your EPS image instantly into a PDF (ideal for emailing), just drag it onto Apple’s Preview application icon in your dock (or in your Applications folder) and Mac OS X automatically converts your Postscript file to a PDF on the fly.
When you choose save from the File menu, it will save as a PDF.

Assigning Color Profiles:
Preview lets you color manage photos. You can assign an ICC color profile for any open JPEG or TIFF image by going under the Tools menu and choosing Assign Profile. This brings up a dialog with a pop-up menu of available color profiles. To assign a specific profile, just choose it from the pop-up menu, then click OK.

If instead you want to change the color profile to match a specific ColorSync profile, then go under the same menu, but instead choose Match to Profile. A dialog will appear where you can choose the source, and which profile you want to match.

Seeing a Photo’s EXIF Metadata:
When you take a photo with a digital camera, a boatload of background information is embedded into the file (called EXIF metadata), including when the photo was taken, the make and model of the digital camera, the exposure, shutter speed, lens focal length, whether the flash fired, and a host of other related info. Believe it or not, Preview can display all this EXIF metadata — you just have to know where to look.
To see the EXIF data for the current image, just press Command-I, then click on the Details tab, and if you scroll down a bit, you’ll see a header for EXIF Properties, along with the full scoop on your image.

Converting to TIFF, JPG, or Photoshop:
Want to change most any graphic into a Photoshop file? Just open the file in Preview, go under the File menu, and choose Save As…, where you can export your graphic in Photoshop format. But you’re not limited to Photoshop format — Preview will also export your file as a JPEG, PICT, BMP (for sharing files with PC users), PICT, Targa (for video), and more. If the format you’re saving in has options (such as quality and compression settings for JPEG and TIFF images), they will appear near the bottom of the dialog.

Hidden Sorting Options:
When you open multiple images in Preview, they appear in the Drawer. You can sort them manually by dragging them up and down the list, but there’s another way—if you Control-click on one of the images in the Drawer, a contextual menu will appear, and you can then sort by name, size, keyword, and more.

Create Your Own Icons:

You don’t have to live with the icons your Mac displays by default. Instead, personalize your folders, files, and drives with custom icons using just about any graphic file you desire, whether it’s a jpeg, gif, png, Photoshop or Illustrator file, or even a PDF.

First, choose an image you want to use and open it in Preview. If the file doesn’t open in Preview by default, select the image in Finder, select Open With from the File menu and then select Preview from the drop-down list.

Once your image has opened in Preview, press Command-C to copy it.

Next, select the file, folder or drive whose icon you want to change, and press Command-I to show its Info window.

Click the file, folder, or drive icon at the top left corner of the Info screen, then press Command-V to replace this icon with your chosen image.

Close the Info window. The new image should appear in place of the old icon on your desktop or Finder window — even in List view.

To make your icons appear larger or smaller, go to the Finder and select View Options from the View menu. Use the slider in the pop-up window to change your icons’ display size on the desktop or in Finder windows.

You can also copy icons from the Info window of one file, folder, or drive to another. Just select the desired icon, copy it, then select the icon you want to replace and paste. Want to revert to the default Mac icon? Select your custom icon in the Info window and press the Delete key.

More Icon Tips: The most successful icons are clear, small images without too much detail, like a close-up photo of a face or a flower. You may want to crop an existing image down to a single detail in an image-editing program to create a better-looking icon — or use one of the thousands of purpose-made icons available in various online collections.

Keep in mind that using a large image as an icon increases the file size of your destination folder or file. For example, using a 3.4 MB photo as an icon for a 36 KB document increases that document’s total file size to 92 KB. Try creating a lower-resolution or smaller version of your image instead.