The Photo Format Your Phone Never Sends
Your phone almost certainly stores photographs in a format no browser will display. That is a strange situation for 2026, and the explanation has very little to do with which encoder produces smaller files. Image formats succeed or fail on licensing, and the history of the last thirty years is mostly a history of that.
JPEG endured by arriving first
ISO/IEC 10918-1 was published in 1992. It defines discrete cosine transform coding on 8x8 blocks, which is why heavy compression produces those blocks as visible artefacts — you are seeing the coding structure itself.
Technically JPEG has been beaten repeatedly. It survives because a baseline decoder exists in every operating system, every browser, every camera, every printer driver and every piece of software written since the mid-1990s. Nothing that came after has matched that, and for a file that must open on unknown equipment, universality outranks efficiency.
PNG exists because of a patent
GIF used LZW compression. Unisys held a patent on LZW and began pressing for licence fees from software authors in the mid-1990s, which made GIF encoding a legal question rather than a technical one.
The response was PNG, designed publicly on a mailing list and finished quickly, using the unencumbered DEFLATE algorithm. It became a W3C Recommendation in 1996 and an ISO standard in 2004. It is lossless, it carries an 8-bit alpha channel, and being free of royalties was not a side benefit — it was the entire specification brief. PNG is what a format looks like when a community builds it in reaction to a licensing problem, and it is worth remembering that outcome when reading the next two sections.
HEIC won the camera and lost the browser
HEIF was standardised in 2015 as ISO/IEC 23008-12. Apple adopted the HEVC-coded variant, HEIC, as the default camera format in iOS 11 in 2017, and the compression is genuinely good — roughly half the size of a comparable JPEG, with support for depth maps, image sequences and 10-bit colour.
No browser will decode it.
The reason usually given is HEVC's patent position. The video codec underneath is covered by claims administered through several separate licensing pools with overlapping membership, and shipping a decoder to hundreds of millions of users means resolving all of them. That calculation was straightforward for a hardware manufacturer selling devices, and unattractive for anyone giving a browser away.
The practical consequence is the conversion step you have probably already met: photographs that must leave the Apple ecosystem get turned into JPEG or WebP on the way out. Excellent compression, in a container the open web declined to accept.
WebP and AVIF learned the lesson
Google announced WebP in 2010, deriving its lossy mode from VP8 keyframe coding, with lossless and alpha support following in 2011. Adoption was slow for years and then abruptly complete: Safari added it in version 14 in 2020, at which point WebP became a format you could simply use. That is the reason it is the sensible default for a photograph on a web page, not the compression ratio.
AVIF, from the Alliance for Open Media, is built on AV1 intra-frame coding and was specified in 2019. It compresses better than WebP, particularly at low bitrates, and it was royalty-free from the outset by explicit design. Chrome shipped decode in 2020, Firefox in 2021, Safari in 2022. It reached the web in roughly three years — about the time HEIC has spent not reaching it.
JPEG XL is the interesting failure. It is technically strong, offers lossless recompression of existing JPEG files, and is free of royalties. Safari shipped it in 2023. Chrome removed its experimental support the same year, citing insufficient ecosystem interest, and without agreement between the major engines a format cannot be deployed on a public page. Being good and being free is not sufficient. Arriving after the incumbent is entrenched is a real handicap.
Choosing, in practice
Photograph headed for a web page: WebP, or AVIF where you can produce it. Anything that must open on unknown or older software: JPEG. Screenshots, diagrams, logos, anything built from flat colour and hard edges, or anything needing lossless transparency: PNG. Camera original you want to keep: leave it exactly as it is, in whatever the camera wrote.
Our image converter offers WebP, JPEG, PNG and BMP, and lists AVIF only when your browser reports an encoder that actually works — most do not, which is why the entry usually is not there. It cannot read HEIC either, because the browser it runs in cannot. For those, use the export options in your phone's photo application or a dedicated desktop encoder.
One thing worth more than any of this: for most images on most pages, shipping fewer pixels beats switching container. A 4000-pixel-wide photograph displayed in an 800-pixel column is wasting far more bytes than a format choice can recover, and Resize Image fixes that in one step.