A format nobody can open is a photograph you no longer have
The Photo Formats Your PC Can and Cannot Open
You copy the photos off a phone or a camera and the folder fills up with gray rectangles. Nothing has broken. The picture is inside a container your computer was never taught to read. Here is what is actually documented about each of these formats, by the people who publish them.
The format your phone chose for you
The most common reason a photo will not open on a Windows PC is that it came off an iPhone as a .heic file. Apple’s support document Using HEIF or HEVC media on Apple devices, last published on 5 December 2025, says iOS 11 introduced “HEIF (High Efficiency Image File Format) for photos” and “HEVC (High Efficiency Video Coding), also known as H.265, for videos.”
Two details on that page are routinely mangled elsewhere. The first is that Apple never uses the word “default.” It says “capturing in HEIF and HEVC format is recommended,” and it lists exactly which hardware can capture it at all: “iPhone 7 or iPhone 7 Plus or later,” plus specified iPad generations and Apple Vision Pro. An iPhone 6s has never produced a HEIC file.
The second is what the escape hatch actually does. Apple’s instruction is “Open Settings, then tap Camera. Tap Formats, then tap Most Compatible,” and the consequence, in Apple’s words, is that “all new photos and videos will now use JPEG or H.264 format.” Photos and videos: anyone who flips that switch to fix one stubborn PC also changes the codec of every video they shoot from then on.
What Windows opens on its own
WIC codecs from Microsoft on Microsoft Learn, last updated 14 May 2025, separates codecs “built into Windows” from “extension codecs downloadable from the Microsoft Store.” Native, in the box: BMP, DDS, DNG, GIF, HD Photo, ICO, JPEG, JPEG XR, PNG and TIFF. Extensions you have to add: HEIF, raw, and WebP. AVIF and JPEG XL do not appear on that page at all. Everything modern is a bolt-on.
The bolt-on for iPhone photos is where a widely repeated claim goes wrong in both directions. Microsoft’s own support article on the Photos app tells you to “buy both of these extensions from the Microsoft Store,” namely “HEIF Image Extensions,” which it marks as free, and “HEVC Video Extensions,” which it marks as a paid purchase — and then adds the sentence people miss: “You’ll need both, even if you only plan on using photos and not videos.” The reason is structural. A HEIC file is a container, and the picture inside it is compressed with the video codec. Microsoft’s Store listing for the free HEIF extension states it plainly: “The HEVC Video Extensions package must be installed in order to view images stored in HEIF files.”
Microsoft’s other suggestions are conversions rather than fixes: re-import over USB, because “many devices will automatically convert HEIC photos and HEVC videos to a more common format when transferring,” or upload to OneDrive and let it convert. Hold that thought, because a conversion is a rewrite.
AVIF and WebP: the web formats
These two arrived from the web rather than from cameras, and they are increasingly what you get when you save a picture out of a browser.
WebP is Google’s. Its own developer documentation says “WebP lossless images are 26% smaller in size compared to PNGs” and “WebP lossy images are 25-34% smaller than comparable JPEG images,” and that it is “natively supported in Google Chrome, Safari, Firefox, Edge, the Opera browser.” Chrome’s platform-status record has it enabled by default since Chrome 9, in 2011.
AVIF is from the Alliance for Open Media, and the relationship people get wrong is worth stating precisely. The AV1 Image File Format specification, version 1.2.0 dated 16 October 2025, says that an AVIF file “is designed to be a conformant [HEIF] file.” AVIF is not a competitor to the HEIC container; it is that container, holding AV1 data instead of HEVC data. Chrome has decoded it by default since Chrome 85, and Mozilla’s MDN lists support in Chrome, Edge, Firefox, Opera and Safari.
That shared plumbing explains the Windows behavior. Microsoft’s HEIF extension listing says that as well as HEVC for .heic, “the AV1 Video Extension package must be installed in order to view images stored in HEIF files that use the .avif file extension.” Two free extensions and AVIF opens; one free extension and WebP opens. The trap is not cost. It is the assumption that a file which displays in your browser will display on your desktop — those are separate stacks, and a file that renders perfectly in a Chrome tab can still be a gray rectangle in File Explorer on the same machine.
JPEG XL, removed and reconsidered
JPEG XL has strong technical credentials and genuinely unsettled support, and almost everything written about it is out of date within a year.
The JPEG committee’s own overview describes it as standardized in ISO/IEC 18181, with a reference implementation that is “free and open source, royalty-free.” Its most distinctive property is that “existing JPEG files can be losslessly transcoded to JPEG XL… and can be restored into the exact same JPEG file.” Apple’s WebKit team, announcing support in Safari 17, put a figure on it: recompression “without any loss of data, while reducing their size by an average of 20%.”
Safari shipped it. Chrome removed it, having never enabled it by default. What gets reported as an aesthetic dispute was, in Mozilla’s telling, an engineering one. Mozilla’s public standards position, merged on 4 September 2024, states the objection exactly: “Our primary concern has long been the increased attack surface of the reference decoder… which weighs in at more than 100,000 lines of multithreaded C++.” The resolution proposed there was a rewrite in Rust. A Chrome Platform Status entry created on 26 December 2025 records exactly that: JPEG XL decoding in Blink “using jxl-rs, a memory-safe pure Rust decoder.”
For an archive, that is neither a reason to adopt it nor a reason to dismiss it. It is a reason to wait, because a format whose availability has changed three times in four years has not yet demonstrated the one property an archive needs.
Raw is not a format
“Raw” sounds like a format in the way that JPEG is a format. It is not. The Library of Congress, in its Sustainability of Digital Formats description of camera raw, calls it a “collective description of a group of proprietary formats employed by digital cameras,” and lists .cr2 and .crw (Canon), .nef (Nikon), .arw and .srf (Sony), .raf (Fuji), .orf (Olympus), .pef (Pentax), .dcr and .kdc (Kodak), .mrw (Minolta) and .x3f (Sigma) — a sample, not a census. Canon alone later added .cr3.
The Library is unusually direct about what follows: “There is very little disclosure of raw format specifications by manufacturers,” and “there is a risk that any given format will not be supported for the long term, especially if the manufacturer goes out of business. In at least one instance, data elements have been encrypted within a raw format, forcing the use of the manufacturer’s own software for post-processing.”
Windows will show you many of these, but only after you install something. Microsoft’s Raw Image Extension is free, requires the Windows 10 May 2019 Update or later, and is candid that it “supports a long list of cameras, however some Raw formats like GPR are not currently supported.” Its Store description also credits its engine: “this package is made possible thanks to libraw open source project.” Microsoft’s ability to open your camera’s files rests on an independent open-source project.
DNG is the attempted answer. The Library of Congress describes formats “that normalize camera raw data, like Adobe’s DNG” as “intended to mitigate this risk,” and notes that a DNG “may also contain a copy of the raw file as created.” It is on the Library’s accepted list, and one of the few modern formats with a codec built into Windows rather than bolted on. But read Microsoft’s documentation for that codec carefully. The DNG Format Overview on Microsoft Learn states that the native decoder supports the DNG 1.4.0.0 specification, and then: “The decoder does not support decoding raw sensor data and only supports files with a non-raw image representation embedded in an IFD.” Windows is not developing your raw file. It is finding a ready-made preview tucked inside it and showing you that — so the thumbnail can look perfect while the photographic data remains unopened.
TIFF and PNG, and where each is right
TIFF is the format the scanning and print worlds settled on. The Library of Congress records its disclosure as “fully documented,” with the governing revision — TIFF, Revision 6.0 — finalized on 3 June 1992, and notes that particular subtypes are “very widely deployed as master formats for scanned images.” It also flags the honest weakness: the tag set is extensible through a registry, and “the list of registered extensions is not available from Adobe.” A file can be valid TIFF and still use a compression your program does not know.
PNG has the cleanest paperwork. The Library of Congress records it as an “open standard and fully documented,” published as ISO/IEC 15948:2004 and, most recently, as the PNG Specification (Third Edition), a W3C Recommendation dated 24 June 2025. It is lossless, handles transparency and has a native Windows codec, which makes it the correct answer for screenshots, scans, line art and anything with text in it. What it is not is a good conversion target for a photograph you already hold as a JPEG: the compression damage is already baked into the pixels, the file gets very much larger, and — historically — your camera data was thrown away.
The formats side by side
“What opens it today” below describes an ordinary Windows PC with nothing added, using Microsoft’s published codec list of 14 May 2025 and its Store listings as checked on 31 July 2026.
| Format | What it is good at | What opens it today | Archival risk |
|---|---|---|---|
| JPEG | Photographs you intend to share, view and hand to anybody | Everything. Native Windows codec, every browser, every phone | Very low. Lossy, so never re-save repeatedly, but it is on the Library of Congress accepted list |
| HEIC / HEIF | Storage efficiency on the device that shot it | Windows extension codec. Needs the free HEIF extension and an HEVC extension | Moderate. On neither Library of Congress list; depends on a paid or vendor-supplied codec on Windows |
| AVIF | Web delivery; royalty-free; HDR and wide color gamut | Not on Microsoft’s native list. Needs the free HEIF and AV1 extensions. All major browsers | Moderate. Openly specified, but young and absent from national-archive lists |
| WebP | Smaller web images; 26% smaller than PNG losslessly, per Google | Windows extension codec, free. All major browsers | Moderate. Widely implemented, but not a preservation format anyone recommends |
| JPEG XL | Lossless recompression of existing JPEGs, reversibly | Safari since version 17. Not on Microsoft’s codec list. In Chromium behind a flag | High for now. Strong specification, unsettled implementation |
| Camera raw (CR2, CR3, NEF, ARW, RAF, ORF…) | Maximum latitude for editing; the closest thing to a negative | Free Windows Raw Image Extension, built on libraw, with gaps | High. Proprietary, largely undisclosed, one format per manufacturer per era |
| DNG | Normalizing raw into one documented container | Native Windows codec — but it reads only the embedded preview, not the sensor data | Lower than proprietary raw. On the Library of Congress accepted list |
| TIFF | Scans and master copies; high bit depth; uncompressed | Native Windows codec. Universal in imaging software | Low. A Library of Congress preferred format. Watch for exotic compressions |
| PNG | Screenshots, text, line art, transparency, anything lossless | Native Windows codec. Every browser since the 1990s | Low. A Library of Congress preferred format; W3C Recommendation, June 2025 |
Where capture dates disappear
Every fix above is a conversion, and a conversion is a rewrite. Whether the capture date survives depends on whether the destination format has a defined place to put it and whether the program chose to fill it in. Both fail more often than people expect.
Take PNG. The PNG Specification (Second Edition), a W3C Recommendation dated 10 November 2003 and the version most software was written against, contains no Exif chunk whatsoever — the string does not appear in the document. A standard place for camera metadata in a PNG arrived only with the Third Edition in June 2025. For roughly two decades, “save as PNG” had nowhere standard to put your capture date. Even now the specification is careful: the eXIf chunk “contains metadata concerning the original image data,” and if the image has been edited since, “the data should be considered to be of historical value only.”
WebP is better but conditional. Google’s container specification defines an “optional ‘EXIF’ Chunk with Exif metadata” — but only within the extended file format. A WebP written in the simple format has no structural place for a capture date at all.
And the conversion can happen without you asking. Apple documents it: “When you import HEIF or HEVC media from an attached iPhone or iPad into Photos, Image Capture, or a PC, the media might be converted to JPEG or H.264,” unless you turn on Keep Originals. That single setting is the difference between copying your photographs and re-encoding them.
What an archive should be in
There is a published answer to this, from an institution with no product to sell and a mandate measured in centuries.
The Library of Congress Recommended Formats Statement lists, for “Photographs — Digital,” three preferred formats: TIFF (.tif), JPEG 2000 (.jp2) and PNG (.png). Its acceptable formats are JPEG/JFIF, Photoshop PSD, JPEG 2000 Part 2, Digital Negative DNG, proprietary camera raw formats, and GIF. Its preferred technical characteristics are the highest resolution available “not rescaled or interpolated,” the highest bit depth available, an embedded color profile, and uncompressed data.
Now notice what is not there. HEIC is on neither list. Neither is AVIF, nor WebP, nor JPEG XL — all efficient, modern, openly specified and technically excellent. The most efficient format in this article is on neither list, and the format the Library prefers above all others was finalized in 1992.
The property being selected for is not quality and it is not efficiency. It is that the specification is openly published and that many independent programs have implemented it, for long enough that no single company’s decision can withdraw your ability to read the file. That is a slow property: a format cannot have it when it is new, however good it is, and it can lose it when its only implementation belongs to a vendor.
The practical conclusion is duller than the debate. Keep the original exactly as the camera wrote it; nothing you convert to will ever contain more. For the copy that has to survive you, use something on that preferred list. And do not re-encode a JPEG library into anything: JPEG is already acceptable to the Library of Congress, and a lossy re-encode is a real loss in exchange for nothing.
Format choice is only one of the three ways a photo library quietly disappears. The other two are the medium underneath it and the assumption that a copy exists somewhere — covered in how long burned discs actually last and why sync is not a backup.
Open one file you have never opened
Find the oldest folder you own that came off a camera rather than a phone, and try to open one file in it. Twenty minutes now tells you more about your archive than any table can.
How long do burned discs last? Fix wrong photo datesFrequently asked questions
Why will my PC not open the photos from my iPhone?
Because they are HEIC files, and Microsoft does not include a HEIF codec in Windows. Microsoft's own list of imaging codecs, updated on 14 May 2025, classes HEIF as an extension codec downloaded from the Microsoft Store rather than one built into Windows. Apple's documentation explains the file itself: iOS 11 introduced HEIF for photos and HEVC for video.
Do I have to pay to open HEIC files on Windows?
Partly, and this is widely misreported in both directions. Microsoft's support article tells you to install two extensions: HEIF Image Extensions, which is free, and HEVC Video Extensions, listed at 0.99 US dollars when checked on Microsoft's Store on 31 July 2026. The article states that you need both even if you only plan on using photos and not videos, because the picture inside a HEIC file is compressed with the video codec. Microsoft also publishes a separate listing called HEVC Video Extensions from Device Manufacturer, which shows no purchase price.
Should I switch my iPhone to Most Compatible?
It depends what you are trying to fix. Apple's documentation says that after tapping Settings, Camera, Formats, Most Compatible, all new photos and videos will use JPEG or H.264 format. It changes video as well as stills, and it applies only to new captures, so it does nothing to the library you already have.
Can Windows open my camera's raw files?
Usually, after you install Microsoft's free Raw Image Extension, which needs the Windows 10 May 2019 Update or later. Its own Store description says it supports a long list of cameras but that some raw formats, such as GPR, are not supported. Raw is not one format: the Library of Congress describes camera raw as a group of proprietary formats, listing CR2 and CRW, NEF, ARW and SRF, RAF, ORF, PEF, DCR and KDC, MRW and X3F among others, and notes that there is very little disclosure of raw format specifications by manufacturers.
Is JPEG XL supported now or not?
Both confident answers are wrong. Safari has supported it since Safari 17, and a memory-safe Rust decoder called jxl-rs is now in Chromium, recorded in a Chrome Platform Status entry created in December 2025. But as of 31 July 2026 that entry still reads Proposed, and the code is gated behind the enable-jxl-image-format flag and the enable_jxl_decoder build flag. Microsoft's list of Windows imaging codecs does not mention JPEG XL at all. It is neither dead nor shipped.
Which format should a family photo archive be stored in?
The Library of Congress Recommended Formats Statement lists TIFF, JPEG 2000 and PNG as preferred formats for digital photographs, and JPEG, PSD, DNG, proprietary camera raw and GIF as acceptable. HEIC, AVIF, WebP and JPEG XL appear on neither list. The practical reading is to keep every original exactly as the camera wrote it, use a preferred format for any master copy you create, and not re-encode an existing JPEG library.