I love the animated GIFs that I find on NASA and other science sites, but when I go to print them in my class handouts, it’s the first frame that’s shown. How can I extract a specific frame from an animated GIF on my Mac system?
You’re spot on that the National Aeronautics and Space Administration (NASA) has some fantastic animated GIF images. Turns out that the sequences of photos that satellites and probes take are perfect for the flip-book-esque characteristics of an animated GIF, as they’ve long since figured out. The one I most recently bumped into is a rather mind-boggling sequence of the moon traversing across the face of the Earth, all taken from a million miles out in space.
I know, it sounds like some sci-fi movie special effect – and it’s definitely something we’ve seen in plenty of movies and TV shows! – but this isn’t a computer rendering, it’s the actual thing. The page is aptly titled From a Million Miles: NASA Camera Shows Moon Crossing Face of Earth. Click on that and go check it out, the page itself is super interesting and budding young scientists will be excited by the imagery for sure.
But how do you extract a single frame? Turns out that’s a rather laborious process, though not difficult. Let me show you how to use the Mac program Preview to do all the work.
To start, however, here’s the animated GIF sequence from that NASA page:
I could just sit and watch that all day, actually. So amazing to think that we have cameras so far from our planet that they can capture these sort of images and successfully transmit them back to us for analysis!
Download this image from the site (easy: Right-click or Control-click on the image and choose “Save Image As…” to do so) and double click it to open it up in the mighty Preview program. Here’s what you’ll get:
As you can see, each frame of the animated GIF is shown as a different image on the left side, which is great. Using the arrow-down key, you can step frame by frame to find the image that you find most appealing. Me? I like frame 9 quite a bit:
Now the easiest part of the process: Simply drag the thumbnail of the frame you want from the left side list to the Desktop.
It’ll show up, but as a TIFF file, rather oddly:
Almost there. In fact, you can use it as-is if you want, though TIFF images tend to be rather large. Instead, let’s go through one more step and double click to open it up again – in Preview! – and change it to a JPEG file.
Opened up, you’ll see just the single frame:
I think it’s funny that “(dragged)” is added to the image name, actually. Somewhere in Apple there’s a programmer who is quite the literalist!
Anyway, choose “Export…” from the File menu:
Here you’ll see a standard file save dialog box, but pay attention to the bottom portion, where you can choose what format you want:
I chose “PNG” as a format rather than a JPEG, because it’s got all the same benefits but also produces a smaller file in almost all cases. Note also that I gave the file a better and more descriptive name too: moon-transit-pic9. A click on “Save” and it’s done.
Really, an extraordinary picture! And it’s in a handy PNG format, ready to add to your class or lecture notes, whether you’re using Microsoft Word, Pages or even just a Web page editor to assemble things.