Why your iPhone photos won't upload, and how to fix it without ruining them

This is one of the most common small frustrations with a modern phone, and it has been for years. A photo that looks perfect on your screen will not attach to a government form, will not open on an older Windows laptop, or gets rejected by a website with an error that explains nothing. People then do what the internet tells them to do, which is convert the file, and a good number of them find the result is bigger, a little different in colour, or still refused.

This post looks at what people actually report, explains in plain terms what is going on, shows measurements we took on a test photo, and sets out the right way to handle it. It also includes something we found while testing: a colour problem that affects a lot of converters, including ours until we fixed it for this post.

What people actually run into

Six different places, one story. The photo is not broken. Whatever is on the receiving end was written to expect JPG or PNG and has no plan for anything else. Three of the six threads end with no fix at all, which is telling. The advice scatters across phone settings, transfer settings, Mac menus and converter apps, and nobody explains which one applies to which situation.

What HEIC is, and why your phone uses it

HEIC is a way of storing a photograph that fits the same picture into roughly half the space of a JPG. Apple made it the default on iPhones in 2017 because phone storage is limited and photos are numerous. It is a good format. The problem is only that it is newer than the software around it.

Support is uneven. Apple's own apps open it without fuss. Many websites, upload forms, older programs and some Windows setups do not, and a form that was written to accept JPG and PNG will simply refuse anything else. There is no hidden fault with the photo. It is a mismatch between what the phone saved and what the other end was built to read.

The two phone settings people mix up

The threads keep circling the same confusion, because the phone has two separate settings that sound alike. Both live in Settings, and they do different jobs.

1. 1How photos are takenUnder the camera format options, you can choose High Efficiency or Most Compatible. Most Compatible makes new photos JPEG. It affects only photos taken after you change it, and the files are larger. It does nothing for the photos already in your library.
2. 2How photos are moved to a computerUnder the photos settings there is a transfer option with Automatic and Keep Originals. Automatic converts only when the computer is judged unable to read HEIC, which is why it sometimes appears not to work on newer systems. Keep Originals always sends the HEIC file.
3. 3Neither one touches photos already on the phoneThat is the case in the 2023 thread with thousands of old files. For existing photos you need a conversion, not a setting.

What a conversion costs: size

A converted JPG is bigger than the HEIC it came from. That is not a fault of the converter. It is the same picture stored in a less efficient format. To see how much, we took a 3840 by 2160 photograph, saved it as a HEIC, and converted it back to JPG with our tool and with Apple's own command line converter at three quality settings.

Two practical points follow. First, do not convert the whole library out of habit. You pay in storage for something you may never need. Convert the photos that have to go somewhere that cannot read HEIC. Second, if a form has a size limit, a freshly converted photo may now exceed it. Lower the quality a little, or resize the picture, rather than converting again.

What a conversion costs: colour

The February 2025 thread mentions, almost in passing, that the HEIC versions looked brighter. That detail deserves attention, because it points at a real problem that few guides mention.

iPhones write photos using a wide range of colour called Display P3. Most of the internet, and most upload forms, assume the smaller range called sRGB. When a converter changes the file to JPG, it has to translate the colour numbers from one range to the other. If it skips that step and only relabels the file, every colour comes out slightly duller than the original. The picture still looks reasonable. It just looks less alive than it did on your phone, and it is easy to miss without the original beside it.

We tested this properly while preparing this post. We made a test image of four colour bands, saved it the way an iPhone does in Display P3, and ran it through our own converter. It failed the test. The colours were noticeably off, so we fixed it, and the table shows both results next to the correct values.

What else changes in a conversion

• Camera and location details are not carried over. The converted file is written fresh from the picture. In our test, a camera make stored in the HEIC was gone from the JPG. That is good for privacy and a loss if you wanted the date or the camera recorded.
• The picture is encoded again. Going from HEIC to JPG applies lossy compression a second time. At a high quality setting you will not see it, but it is the reason to convert once, from the original, and not repeatedly.

The right way, depending on the situation

You need to send a few photos right now

Convert those photos and leave the library alone. Choose JPG at about 90 percent quality, which is the sensible default. Check the result opens, and check it is under any size limit the form states.

A form has a size limit as well

Convert first, then reduce. Trying to do both at once is where people lose quality twice. If the converted file is still too large, resize the picture to a more modest size, or compress it to a target.

You will send photos like this all the time

Change the camera setting so new photos are saved as JPEG. You will use more storage, and you will not have to think about it again. Existing photos need a one off conversion.

The photos are private

Think before pushing identity documents, medical images or family photos through an online converter. Most upload the file to a server somewhere. A converter that runs in your browser does the same job without the file going anywhere, and you can check that by watching your network activity while it runs.

Mistakes that waste the afternoon

• Renaming the file. It does not convert it, and a form that checks contents will still refuse it.
• Converting the whole library to be safe. The files are larger and you only needed a few.
• Converting a photo that was already converted. Each pass loses a little more. Go back to the original.
• Using a converter that strips the colour. Check against the original on a screen, as described above.
• Forgetting the size limit. A converted photo is larger. Check it before you submit.
• Trusting the transfer setting. Automatic converts only sometimes. If the file type matters, look at the result.

A short routine to keep

Work out whether the place you are sending to accepts HEIC. If not, convert only the photos you need, from the originals, at about 90 percent. Check the colours look right beside the original and the size is under the limit. If this will keep happening, switch the camera to its most compatible setting and stop thinking about it.