MacMost Now 207: Using Preview to Cut Out Part of a Photo

Use the Preview application that comes with Mac OS X to cut out a person or object from a photo and make the rest transparent. You can use this to make better images for social network profiles, Pages documents or Keynote presentations.

Video Transcript
On today's episode lets learn how to use Preview to cut out part of an image and leave the rest transparent.
For those of use who have used Photoshop and other tools like that know that this is a pretty common thing. You want to take a person that's in an image and cut them out or some object in it and cut it out and leave the rest transparent. Make the background transparent in other words. There are a lot of different uses for this. For instance, you can use it to cut yourself out of an image and use that as an icon for one of the social networks like Facebook. There's a lot of other uses. But this, you know, you can do it with the Preview tool that comes with Mac OSX 10. The Preview is full of surprises and here's how to use it to go ahead and cut out somebody from an image.
Ok, so here's an image of me that I just pried out of my iPhoto library. Now it really helps to have a high-resolution image, so something form your iSight probably won't work. You want something from your digital camera, 5 mega pixels or higher, so that you have a lot to work with for removing pieces of the image.
The first tool we're going to go ahead and use is up here in the selection tools and it's called instant alpha. What happens, is you grab the little pieces draw basically little lines
on the screen and it grabs the colors in that area and it will highlight them in red and then remove them. And continue to grab different areas of the image. Now this is going to be a difficult image to work with because of those shadows there behind me. They're going to go into my beard like that and it's going to be very hard to remove. You can do a pretty good job though and get rid of a lot of it.
So a better way to do it might be to actually go ahead and start again here. So to use this method it's called the extract shape method. It's the same place; it's the one right above it there. And what you do here is you want to draw around the shape you want to extract. You're going to draw this red line here. And you can release your mouse and click it again to continue to add to the line. It won't complete the shape until you get all around and connect back to the original piece. So you want to kind of outline what's there the best you can. You can zoom in, definitely in the preview window there, and get little bit more accuracy. But you're going to have chance here in a second to go ahead and make it even more accurate when you're done drawing the initial shape.
So you're just going to draw straight across, connect it, and there we go. Now I get all these little dots, and I can actually manipulate these dots and move them around to kind of hone in the exact image I want. And again I can zoom in or leave it at this zoom here. And hit return and it will cut out everything except what's there.
So the great thing is here I have an image now basically of me that has no background around it. I can use it as a nice icon on Facebook or something else. You can see that it's kind of rough around the edges like around my ears, but this is where the high resolution comes in. Because I'm not going to use it at this kind of resolution, I'm going to go ahead and save out of Preview in a different resolution. So I mean this thing may be a couple mega pixels still in size. I'm going to and save it in something really small like maybe 320x320 or 160x160, and you're not going to see those little jaggies around and that's the advantage of starting with a high resolution image. Now if you save the image out like a png file it will maintain the alpha transparency. In other words the transparent part will remain transparent. So you can go ahead and use it in something like Pages for instance and drop a graphic in there. So say you that have a picture of a product that your company makes and it has all kind of stuff in the background, you can cut that product out and make a nice transparent version of that and you can put that image into your presentation using Pages, you can use Keynotes, all sorts of things, and create a nice image for that. The key is the png that's 32 bits instead of saving it as a jpeg that you might use on the Internet.
So that's all for now, until next time this is Gary Rosenzweig with MacMost Now.

Comments: 43 Responses to “MacMost Now 207: Using Preview to Cut Out Part of a Photo”

    Ronny Fugmann
    2/23/09 @ 2:13 pm


    I really didn’t know you could do something like that with Preview – this is one application that is constantly underestimated.

    Thanks for your let’s-show-you-how-it’s-done-video! :)

    Dick Franks
    2/28/09 @ 7:57 pm

    A fun unexpected surprise. Thanks.

    I showed it yesterday to an Apple One-to-One Instructor who was mildly astonished: “Preview can do that!”

    3/4/09 @ 5:36 pm

    Thanks MacMost! This episode has helped me VERY much!

    K Tyalor
    8/11/09 @ 10:20 am

    how do you open the photo on preview to edit. it does not give the options you have explained?
    Thks so much

      8/11/09 @ 10:53 am

      Many ways. Run Preview and then choose File, Open. Drag and drop the file onto the Preview app (in the finder or doc). Ctrl+click on the file and choose Open With and then select Preview as the app.

    Julia Harryman
    8/12/09 @ 5:40 pm

    Thank you, I messed with this for hours on my own and was unsuccessful until I found your video. Great job!

    9/27/09 @ 6:25 pm

    That was invaluable advice…I have been on the internet for hours trying to figure out how to cut-out photos!

    11/19/09 @ 11:56 am

    Really useful, thanks very much!

    1/18/10 @ 4:56 pm

    What if I want to cut a hole out of an image so that the area inside the whole is transparent as well as the background? I am scanning the image of an actual CD to be used as the CD art for iTunes since I do not have the album cover. Thanks.

      1/18/10 @ 5:35 pm

      You could do that as well by selecting the area and deleting it. Or, in your case you could just fill it with white.

    9/20/10 @ 10:49 am

    what if i want to take out a peice but i dnt want it transparent i just want that chunk of the image gone? like when i save it is still has just a white area wherei wanted to cut out

      9/20/10 @ 10:57 am

      It depends on what you want to use it for. For most purposes, like uploading to sites, it will just fill with white.

    5/10/11 @ 9:13 am

    running Preview on 10.6.7, the smart lasso is still available but: you have to continously press the mouse button, as soon as you release the selection will be “closed” to the starting point. And there’s no option to refine the selection. Too bad, because this was a nice feature in my opinion. Or am I missing something?

      5/10/11 @ 9:35 am

      Right. It looks like they replaced Extract Shape with Smart Lasso. Same thing, but you can’t add to the Smart Lasso like you could with Extract Shape.

    6/24/11 @ 9:42 pm

    i can not find the tools button

      6/24/11 @ 10:28 pm

      Tools button? There is no tools button. What are you looking for?

      Daniel McKinney
      7/1/11 @ 9:24 pm

      I think what you’re looking for is the Select dropdown menu. It confused me too. When he hits the Select icon, he’s actually holding down the mouse rather than just clicking. That’s how you get it to come down.

    Daniel McKinney
    7/1/11 @ 9:22 pm

    I had no idea you could do that! That’s fantastic! Thank you!

    7/27/11 @ 5:51 pm

    Gary I have a problem. How do you delete the red areas? I’m really confused on this.

      7/27/11 @ 6:01 pm

      After you have selected an area in an image, press the Delete key on your keyboard.

    7/27/11 @ 6:14 pm

    Well even with Smart lasso once I complete the circle the red band will disappear and I can’t adjust the dots.

    8/1/11 @ 5:45 am

    When i try to use these tools, it just put a funny looking silver line instead of making the area white :( help please thanks :)

      8/1/11 @ 8:16 am

      Not sure why it would do that. What version of Mac OS X and which version of Preview are you using? Are you trying it with an image file (not a PDF or something else)?

    8/2/11 @ 12:29 pm

    I am using OS 10.6.8 and preview 5.0.3

    Why don’t I have the Extract shape tool you show in the video?

      8/2/11 @ 12:39 pm

      This video is from February, 2009. Extract Shape has now been replaced by Smart Lasso.

        8/2/11 @ 12:41 pm

        I liked the feature where you can fine tune the shape in extract shape after drawing the line. Does smart lasso do that…..and if so how?

          8/2/11 @ 12:57 pm

          I doesn’t appear to do that, no.

            3/14/12 @ 1:18 am

            Hmm, this is the exact info I was looking for when I stumbled on this video and this comment thread. I also miss the feature that lets you can fine tune your selection before validating it. Does “smart lasso” bring anything new that “Extract shape” didn’t do?
            Maybe it’s worth digging and try to run Preview from Leopard :-) What version of Preview was that?

            Cheers for the video, one of the most useful tips I’ve read or seen!

    8/26/11 @ 7:20 pm

    i learnt how to cut figure from different imgae .. now can somebody help me with – after getting different figure from different image .. how to merge them in one image?? thanks in advance..

      8/26/11 @ 7:32 pm

      Copy and paste, basically. Select and copy from one image, then switch to the other image and paste it in there.

    11/28/11 @ 5:39 am

    Thank you from sunny Cape Town

    12/7/11 @ 10:59 pm


    I have to say that now every time I need to do something like this on my mac, this is the first site I come for advice, and always learn something new.
    I was trying to do a multi-image photo for a new site I’m throwing together, and I wanted simplicity without having to open up photoshop. This tip works perfectly!!!
    For those using lion, it also works, but a little different.
    First you select the area using the smart lasso, and then you crop the image or click on Command+K. Same effect.

    Thank you so much for this very useful website and for actually doing every-day tips that regular users need to know for working with their macs. You are a true internet gem.


    1/7/12 @ 1:48 am

    I’ve just scanned a bunch of photos, and it came up in preview documents four at a time. I want to cut out each picture but can’t figure out how to do it. When I crop a picture the one enxt to it disappears.

      1/7/12 @ 9:48 am

      Many ways. Like: Select and copy one of the four. Start a new document with what you have in the clipboard. Save. Repeat.

    2/27/12 @ 3:55 pm

    This helped a lot! The thing that would be most helpful is that you didn’t say if it worked for all Macs. I have an older version, I think Tiger. Does it work on Tiger? Cause no matter how hard I try, it’s not working.

      2/27/12 @ 5:50 pm

      Each version of OS X has added more to Preview. Tiger is very old at this point. I’m pretty sure this functionality didn’t appear until Leopard at least.

    Tim Aych
    3/29/12 @ 10:08 am

    Thanks for this – really helpful :-)
    Please could someone add how I can get rid of the white background though? I cut out an image from a busy background ok, but then when I saved the image and pasted it on to another, there was a large white square around it.

    Please can anyone help?

    Thanks :-)

      3/29/12 @ 10:25 am

      Follow the steps in the video carefully to get a truly transparent image.

    4/26/12 @ 9:16 am

    I love you, you helped me so much.
    Clear video!

    8/13/12 @ 8:42 pm

    For a mom who constantly tries to create invitations and party signs for my son without any computer training or programs to do so, your videos have been a Godsend to me! My son will be very happy with the images of Disney’s CARS that I was able to make transparent!

    8/23/12 @ 3:30 pm

    so i have a mac air bought 2011… i have downloaded pages – in the preview i have it does not have the instant alpha in the selection tools…

    do i have to download something?

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