What Are HEIC Files?

By default your iPhone saves photos as HEIC files. These are compressed images, like JPEG files, but will use less space on your iPhone, Mac and iCloud. You can easily convert these to JPEG files when you need to. Your iPhone also saves video files in HEVC format.

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Video Transcript: Hi, this is Gary with MacMost.com. Let's talk about HEIC files. 
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So years ago if you took a look closely at the files stored in your Photos App you would have noticed that they are JPEG files. But today if you look at your Photos files, especially if you use an iPhone to take photos, you may notice they are not JPEG files anymore, but HEIC files. So JPEG files are compressed image files. As a matter of fact you may have used the terms Image File, Photo, and JPEG file interchangeably. But there are all sorts of image file formats.
JPEG is a very popular image file format that compresses the image. You see when you take a photo, of course, it's made up of pixels. A typical photo today may be 4032 pixels across and 3024 pixels high for a total of just over 12 million pixels. Each pixel, though, has to have a red, green, and blue value to make up the color. So 3X12 is 36 for 36 million pixels or 36 MB. But our photos aren't 36 MB. If you take a look at a typical JPEG photo that's that size it might be 2, 3, or 4 MB in size. That is because it is compressed. A JPEG image, instead of each pixel having its own RGB value, the color is actually estimated based on the other pixels around it. That compresses it a great deal while not hurting the image quality too much. With our eyes we can barely tell the difference between an uncompressed image and a compressed one even though the file size is that much smaller. But the JPEG image format is pretty old. There have been advancements in the field. So there are new better compression formats and one of those is the High Efficiency Format. 
So in 2017 with iOS 11 Apple switched over to having the default format being HEIC, High Efficiency Image Container. This format will give you similar quality to JPEG files but even smaller files size. This will save space on the local storage in your iPhone, your Mac, or your iPad. Also save you space in iCloud Drive. As an aside here that's kind of interesting because a lot of people assume that Apple wants people to spend more money to buy larger drives to get more storage in their iPhone and get a larger storage plan for iCloud that they pay each month. But with this change Apple actually allows us to store more on the same size devices and iCloud Accounts. So Apple is actually loosing money by implementing this. 
Let's take a look a how much space is saved. I have a photo here that instead of taking and compressing it I actually took it in raw format on the iPhone. So every pixel retained its own individual red, green, and blue value. Then I exported it in a format that's supported that, a Tiff. A Tiff file format is very old and each pixel is stored individually. So if I were to look at this photo here and get info on it, I can see it is 4032 by 3024 pixels and that does indeed total just over 36 MB. So this is uncompressed. Now in the Preview App we can actually export in a variety of different formats. So let's go to File, and then Export. Then I'm going to use the JPEG format and I'm going to keep the default setting here. So just under best. You can see it is going to save it as a file that's 5.4 MB in size. I'll save that here to the Desktop and we can examine it and see that is indeed 5.4 MB. 
Now let's do the same export here but this time we're going to change the format to HEIC. I'm going to leave the setting at the same default setting there and you can see it is much smaller. 3.4 MB in size. So let's save that out and now if we can verify that indeed the file is that size. Let's compare the quality. Let's go ahead and zoom in on a section of this here so we can see what we're looking at. We can see the individual pixels here. Now let's take a look at the JPEG image and zoom into a similar portion there and we can see it is really hard to tell the difference. If we look at the HEIC format and we zoom in here, again, we can see also that it's very similar in quality. So we're not sacrificing that much of quality by going from 36 MB to 5 MB to 3 MB is quite a saving in space. 
Now a big problem with HEIC files is that they are fairly new. Like I said before 2017 you couldn't have even open a HEIC file on an Apple product. It continues to be true today for Windows machines and some phones as well. So if you send a HEIC file to somebody chances are they won't be able to open it unless they are using Apple products like you are. But this really hasn't been too much of a problem. As a matter of fact you may have been using HEIC files for a long time at this point and not even realized it and have not had any problems sending it to anybody. That's because when you go to send a file, either in Mail or Messages, it automatically converts it to a JPEG file. 
So for instance here in the Photos App if I select this photo and I get info on it I can see that it is indeed a HEIC file as the source. Yet, if I were to go to Share it and choose Mail I can see it right here. Let's drag this image out of the message here and take a look. You can see peeking out from behind here that it is a JPEG file. It converted from HEIC to JPEG when I created the email message. Not only that, if you just Drag and Drop out of the Photos App you can see it is going to create a JPEG image. Or if you want more control you go to File and then Export and then Export the photo or a group of photos you can choose JPEG or HEIC. Plus sharing online with something like an iCloud Photo Gallery is just going to show it in a compatible format. So they would be on a webpage that somebody would view in a browser and the actual images would be JPEG images stored on the server there. 
So again, no incompatibility issue with that. Now you do have some control of this on your iPhone. If you go on your iPhone to the Settings App and then look for the Camera App settings. Go in there and in Format you can switch the format from High Efficiency to Most Compatible. Most Compatible means JPEG. So you can decide to still have your photos stored as JPEG files, and that is how they would sync across using iCloud Photos. Of course then you're loosing this savings in file size if you do that. 
I should also note that a company High Efficiency Image Containers is High Efficiency Video Containers. If you look in videos here I've got an older video and if I look at that I can see that it's a dot MOV file which is just a container. But inside is a H264 video. If I look at this more recent photo I can see again a dot MOV file. But notice that inside that is an HEVC video file with a greater file saving at the same quality. But if I were to Drag and Drop this out of Photos then the resulting file I would get would automatically be converted. I can select this one, get info on it, and see that it is actually H264. It's been converted. But if I were to select a file here and go to File, Export, and then unmodified original and then export that then I'm going to get a file here that is saved with the original format HEVC. Instead of using Preview I can actually use QuickTime Player to convert this. So I can double click it and it opens up in QuickTime Player. Then if I Export it from here then that export would actually be saved H264 but I also have the choice to save it as HEVC. So QuickTime Player can convert these video files just like Preview can convert image files. 
Now I know I'm going to get asked about older files in your Photos Library. If your most recent ones are using HEIC format and they are smaller because of that, what about your older photos. The ones that are JPEG format. These files, of course, are going to be a little larger than they could be using HEIC. So the question I'm often asked is how do I convert these old ones to HEIC. The answer is really you don't. You shouldn't. First there is no easy way to do it. Even if there was you'd have to actually convert them all. It would be a difficult process. But remember these are already compressed files. So to convert a JPEG to a HEIC would mean compressing a compressed photo. You would be loosing quality doing that. It would be like in the analog days making a copy of a copy on magnetic tape. Each time you do it you loose a little bit of quality. The HEIC files you have now are taken directly from the original capture on your iPhone and compressed right to HEIC. Just as these JPEG photos were taken from the original capture on your phone and converted to JPEG files. So I wouldn't recommend for anybody to even think about converting your old JPEG's to HEIC. Just leave those old files as JPEG and enjoy the smaller file size on the newer photos that you take today. 
So I hope you found this informative and useful. Thanks for watching.

Comments: 5 Responses to “What Are HEIC Files?”

Rick G

12 months ago

This was perfect timing as trying to export an HEIC photo was not working and this vid just explained everything. Thanks.

LaliRaj

Gary I tried exporting a "HEIC" file as JP2 and saved to desktop and checked it actually increase the size of the jp2 file. why?

Gary Rosenzweig

LaliRaj: Do you mean HEIC to jpeg? Then it may be that HEIC is more efficient. Or do you mean jpeg to HEIC. In that case it was probably just the jpeg file compression amount was really high (and lower quality as a result).

Andrea Grasselli

Thank you Gary, really useful!

Pete

4 months ago

Brilliant again. So informative as always and actually useful info. Thank you Gary.