Batch Image Conversion in Mac OS X the Easy Way with Preview

Jan 16, 2013 - 18 Comments

Preview in Mac Preview is a greatly under-appreciated app that has been bundled along with Mac OS X since the beginning, getting better and better with each Mac OS release. One quiet feature that has been around for a while is the ability to mass convert a group of pictures from one file type to another, often referred to as batch conversion. This lets you easily take a large amount of JPG files and convert them over to PNG, for example.

Batch image conversion works with any number of image files and with nearly any image formats. It’s safe to assume that if you can open the image files into Preview app, you can export them to a new file type, including GIF, ICNS, JPEG, JPEG-2000, BMP, Microsoft Icon, OpenEXR, PDF, Photoshop PSD, PNG, SGI, TGA, and TIFF.

How to Convert a Group of Image Files to a New Format with Preview on Mac

Converting large groups of image files this way is really easy in Mac OS X, here is what you’ll want to do:

  1. From the Finder, select a group of images and open them all with Preview, do this either by launching the image files directly or dragging and dropping them into the Preview Dock icon
  2. Once the images are opened in Preview, click within the preview pane on the left side and then Select All, either by hitting Command+A or by pulling down the edit menu and choosing that option – you must select all the images to convert
  3. Pull down the File menu and choose “Export Selected Images…”
  4. Batch convert image file formats in Mac OS X with Preview

  5. Optionally, create a new folder for the converted pictures to save to, otherwise simply select the destination for the files to save to
  6. Now select the desired image format to batch convert all the selected image files to (you can Option-click to reveal more)
  7. Click “Choose” to save and begin the conversion process
  8. Set the destination and file format for converted image files to convert to, then start converting in Preview for Mac OS X

A progress indicator bar will appear over the pictures letting you know things are progressing:

Batch converting images in Preview on Mac OS X

Depending on the amount of images selected to convert, their resolutions – which can also be resized at the same time if desired, and their file formats, this process can either be very fast or somewhat time consuming. Batch conversion of image files is usually quite speedy, but it ultimately depends on the size of the image files, the formats chosen, and the speed of the Mac.

As mentioned, the Bulk Export Images feature in Preview is supported in all versions of Mac OS, including macOS Catalina, MacOS Mojave, MacOS High Sierra, Mac OS Sierra, Mac OS X El Capitan, Mac OS X Yosemite, OS X Mavericks, Mountain Lion, you name it. The interface may look a tiny bit different depending on the version of system software on the Mac.

Batch convert image files in Mac OS X with Preview

The video below walks through the group file type conversion process with Preview, taking a selection of JPG files and saving them to a new folder as PNG’s. As you may notice in the video, the original JPG files remain intact throughout this process.

The ability to convert a single image file has been around for quite some time and that shouldn’t be a mystery to those who have used Preview before, but the group conversion ability is limited to newer versions of the app in Mac OS X.

If you follow us here at OSXDaily with regularity, you probably know that we recently showed how to perform image conversions from the command line using the sips tool as well, but using the GUI and Preview is much easier for most users and is going to have a wider appeal.


Related articles:

Posted by: William Pearson in Mac OS, Tips & Tricks


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  1. Isaias says:

    Great tip. Thanks a lot. It saved a lot of time…!!

  2. Louri says:

    Thank you so much!

  3. Mark says:

    Doesn’t work in El Capitan, can only do up to 5 photos and then gets frozen. Far easier to dump them in Photos and export as jpg.

  4. ansarkk says:

    I can not find the option ‘convert selected images’ just the option ‘Convert’ only in my system why its not visible?

  5. L says:

    This was genious. Thanks for saving me a TON of time!!

  6. Jan says:

    You can convert RAW files by using the export function in Photo why use the extra step of opening them in preview?

  7. RC says:

    This feature is broken in El Capitan. As soon as I select “Export Selected Images” I get an incomplete dialog box, with no export type to choose from. There is a “choose” button, but when I select that, Preview hangs, until I force quit.

    • 5 says:

      Ditto for me: in El Capitan Preview hangs if I try to batch change…

      • Brian says:

        This feature is working in Sierra (10.12.2) While I agree Preview is one of the underrated apps in the Mac OS, Automator is even more underrated and one can create a two step automator task to perform this as well, and many other photo tasks, for instance a task that will duplicate all images as B&W.

        • Hayley says:

          Hi Brian, you mention a two step Automator task to perform this. I would love if you could expand upon this, since I have thousands of jpg (screenshots) I need to convert to individual pdf’s so they can then be OCR’d automatically using Hazel to send them to an OCR programme. Thus far, all I have achieved is being able to select several images and create a single PDF using the ‘New PDF from Images’ Automator action. I need individual PDF’s for each image file however.

  8. Jacob says:

    Thanks a lot.

    If you need to convert a single images to the exact pixels or proportion, and reduce the image size at the same time, you can check out, it supports most popular image formats, enables to resize gifs without losing animation, resize pngs without losing transparency.

  9. James says:

    Thanks for this simple and extremely useful trick. Time to shrink the massive library now!

  10. mike sanders says:

    why can’t I view your video in my email, it is just a black rectangle. OS X 10.8.3
    It has been this way for some time.

  11. Janie Mac says:

    I’ve found the answer: Hold Option while saving


  12. Janie Mac says:

    Am I misreading this?
    I can’t export as GIF from Preview ever since upgrading to Mountain Lion. It used export to GIF in Snow Leopard, but your article leads me to believe I should still be able to export a GIF.

    Only choice I have for export are:

    Where is my GIF option gone?

  13. Connor says:

    I think you can also do this in adobe bridge?

  14. parakeet says:

    Preview is good but it needs some paint tools

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