You take a photo on your iPhone, attach it to an email, and the person on the other end replies: "I can't open this." Or your own email app refuses the attachment before it even sends. The photo is fine on your phone, so what went wrong? The answer is usually the file format: your iPhone saved the photo as HEIC, and the email app — or the recipient's computer — does not know what to do with it.
HEIC is the photo format Apple has used by default on iPhones since 2017. It stores the same image quality as JPG in about half the file size, which is why Apple chose it: your phone holds twice as many photos. The trade-off is compatibility. Windows, older Android phones, and many email clients were built around JPG, and some of them still cannot open HEIC at all.
1. Why email is where HEIC breaks most often
On your iPhone, everything just works, because Apple built HEIC support into the whole system. Email is where the photo leaves Apple's world. Some email apps convert the attachment to JPG automatically; others attach the original HEIC file untouched. And on the receiving end, a Windows PC without the HEIC codec, an older Android phone, or a webmail inbox may show a broken attachment icon instead of your photo. The sender sees a successful send; the recipient sees nothing.
2. The two places the failure can happen
First, your own email app can refuse the file. Some apps check the attachment type and reject formats they cannot preview. Second, the recipient's device can refuse it. A Windows 10 PC, for example, needs a codec from the Microsoft Store to open HEIC, and many people have never installed it. Either way, the photo never gets seen, and neither side gets a clear error message explaining why.
3. The fix: convert before you attach
The reliable fix is to convert the photo to JPG before attaching it. JPG opens everywhere — every email client, every operating system, every phone made in the last twenty years. You lose nothing visible: for a photo sent by email, JPG quality is more than good enough, and the file is small enough to send quickly.
4. How to tell whether a photo is HEIC
On an iPhone, open the photo, swipe up, and look at the file information: it will say HEIC if the photo is in Apple's format. On a computer, check the file extension: .heic means HEIC, .jpg or .jpeg means JPG. If you are not sure, assume any recent iPhone photo is HEIC until proven otherwise — that is the default, and most people never change it.
5. Convert in the browser, then attach the JPG
FileOnTap's free HEIC guide explains the format in plain English, and the converter itself runs entirely in your browser: the conversion happens on your own device, nothing is uploaded, and no account is needed. Open the converter, pick the photo, choose JPG, and download the result — then attach the JPG to your email instead of the original. The whole thing takes less than a minute, and your photo never leaves your phone or computer until you send it yourself.
6. A quick checklist before you hit send
Convert a copy and keep the HEIC original untouched, in case you need the full-quality version later. Open the converted JPG once and check it looks right — face visible, the right way up, colors normal. Check the file size too: most email services cap attachments at around 20–25 MB, and a batch of full-size photos can hit that limit fast. If you are sending several photos, convert them all first, then attach the JPGs in one go.
Email is the oldest file-sharing tool most of us still use, and it is also the least forgiving about new formats. Converting HEIC to JPG before you attach takes a minute and removes the most common reason a photo email fails. The recipient sees your photo, and you never have to explain what HEIC is.
Disclosure: I'm the developer of FileOnTap.
Top comments (0)