There is a moment almost every business owner runs into: you upload an image to your site, and something does not work. The file is “too large”, or the system will not accept it at all, or Google sends a note about “next-gen image formats” and nobody explains what that means.
Behind that confusion sit eight main formats, born across nearly forty years, each one solving a different problem of its era. Here they all are, in order, and what is actually worth using today.
(For those who like exact dates: GIF was released on 15 June 1987, JPEG approved in September 1992, PNG on 1 October 1996, SVG became a W3C Recommendation on 4 September 2001, WebP was announced on 30 September 2010, and AVIF reached version 1.0 on 19 February 2019.)
The timeline, one line per format
| Format | Born | Why it was created | Where it stands in 2026 |
|---|---|---|---|
| GIF | 1987, CompuServe | A colour image down a slow phone line | Outdated for animation |
| JPEG | 1992, JPEG committee | Hard compression for photographs | Still the standard for photos |
| PNG | 1996, the web community | A free GIF replacement, with transparency | Alive, for graphics and transparency |
| SVG | 2001, W3C | Graphics that never pixelate | The right one for logos and icons |
| WebP | 2010, Google | Replace JPG and PNG with a smaller file | The default for websites |
| HEIC | 2017, Apple | Save storage space on the phone | Good on the phone, a problem on the web |
| AVIF | 2019, AOMedia | Harder compression, from a video codec | Mature, not a blanket swap |
| JPEG XL | 2021, JPEG committee | Succeed them all, without quality loss | Stalled, not for production |
”Outdated” is not what you think it is
The most common mistake is assuming an old format is a bad format. That is simply untrue, and two opposite examples show why.
GIF, at 39, genuinely is outdated for its job. It was born in 1987 to move a colour image through a modem, and its central limitation, 256 colours, was a reasonable trade at the time. Today a three-second animated GIF easily weighs several megabytes, while a short video of the same length looks better and weighs a tenth of that. If you have an animated banner on your site in GIF, that is worth a look.
SVG, at 25, is not outdated at all. On the contrary, it is the most correct format for your logo precisely in 2026. The reason: it does not store pixels but drawing instructions, “a line from here to here, a circle of this radius”. So the same file looks perfectly sharp both in a 16-pixel favicon and on a building-sized sign, and it usually weighs less than one small photo. The site you are reading contains 348 SVG files, and together they take up less room than a handful of photographs.
The right question is never “when was the format born” but “what is the job, and which format does it best today”.
The three formats you need to know when uploading
In practice, as a business owner you only touch one side of this: the file you upload. That part is simple.
JPG for photographs. People, products, landscapes, anything that came out of a camera. Its compression was built for exactly that, exploiting the fact that our eyes are forgiving about small shifts in tone.
PNG for graphics and transparency. A logo on a transparent background, a screenshot, an illustration with sharp lines. PNG loses no information, so text and lines stay clean. The price: on a large photograph it can weigh ten times what a visually identical JPG would.
SVG for logos, icons and diagrams. If your designer gave you the logo as an SVG, that is what you hand over. If not, ask. It is worth the email.
What the visitor ultimately receives is no longer the file you uploaded, and that is deliberate. We wrote separately about exactly what happens to an image from upload to the visitor’s screen, but briefly: on a properly built site, every image is converted automatically to WebP at build time and generated in several sizes, so someone browsing on a phone never downloads an image meant for a desktop monitor.
HEIC, or: why your iPhone produces files your website rejects
This is probably the most common failure we see, and it is not your fault.
In 2017, with iOS 11, Apple adopted a format called HEIC. It is excellent: roughly the same image in about half the space of a JPG, saving gigabytes on the phone. The problem is that it is barely supported outside Apple’s world, so when you try to upload a photo straight from an iPhone to a website, a CMS or a form, it is simply rejected.
The fix, and it takes thirty seconds: on the iPhone, Settings, Camera, Formats, and choose “Most Compatible” instead of “High Efficiency”. From that point on, photos are saved as JPG. For photos already taken: send them to yourself on WhatsApp, which converts them to JPG along the way.
AVIF: what changed in July 2026, and what we measured ourselves
AVIF was born in 2019, and it is the format everyone points to as “next”. It is built on a video codec, so it compresses more aggressively than WebP.
Until recently it was easy to dismiss: support was not broad enough. That changed. According to webstatus.dev, the official index we work by, AVIF reached Baseline on 25 January 2024 and became widely available on 25 July 2026. That is two months ago, and it is why this post is being written now.
So did we switch it on? No. We measured first, and what came out was surprising enough to reverse the conclusion we started with.
We took 37 real images from this site, generated from each one the three sizes the site actually serves (400, 800 and 1200 pixels), and got 101 renditions. On the first run, at default settings, AVIF came out 42 percent smaller than WebP. An impressive number, and exactly the kind you are tempted to put in a headline.
Then we looked at the images themselves. AVIF’s default compresses harder than WebP’s default, and in smooth areas, a wall, a sky, a blurred background, it shows: surfaces flatten and lose their grain. The comparison simply was not fair.
So we measured again, this time at genuinely equal quality: we checked how far each format drifts from the source file, and looked for the level at which AVIF is at least as good as the WebP we serve today. The picture that emerged was entirely different:
| Image type | Real AVIF saving at equal quality |
|---|---|
| Detail-rich photograph | 23% |
| Simpler photograph | 13% |
| Screenshot with sharp text | 12% larger |
That last row is worth a second reading: on a screenshot, AVIF at equal quality came out heavier than WebP. That makes sense, because its compression was built for photographs, not for sharp lines and text. On top of that, AVIF encoding took us four and a half times longer than WebP, which feeds straight into every site’s build time.
Our conclusion: WebP stays the default. AVIF is an excellent tool for one specific heavy image, say a large hero photograph at the top of a homepage, not a blanket swap. Anyone selling you “move to AVIF” as an automatic 40 percent upgrade probably compared defaults and never looked at the result.
JPEG XL: the format that was supposed to win
It is worth knowing about only so you understand why it is not on your site.
JPEG XL was standardised in 2021, and it is technically impressive: it can recompress existing JPEG files and save around 20 percent without losing any information, meaning the original can be restored exactly. On paper, a winner.
In practice it fell between the chairs. Chrome removed support in December 2022, reversed the decision only in November 2025, and decoding was merged into Chromium in January 2026. In the Baseline index it is still classified limited, and our policy is clear: a feature that has not reached Baseline does not go onto a client’s site, because a client should not be paying for an experiment.
What this means for your site, bottom line
- Do not convert anything by hand. A properly built site converts and resizes on its own, at build time. If you find yourself shrinking images before uploading, the problem is the site, not you.
- Upload the best quality you have, within reason. There is no point in a 6000-pixel-wide file for an image displayed at half screen width.
- Ask your designer for the logo as SVG, once, and it solves sharpness problems for years.
- Fix the iPhone setting if you upload photos yourself. Thirty seconds that save a lot of frustration.
- Do not chase the newest format. AVIF is mature today, and even it does not suit every image. JPEG XL is not there at all yet.
In summary
Forty years of formats, and in the end the practical answer is short: JPG for photographs, PNG for transparency, SVG for logos, WebP for what the visitor actually receives, and AVIF where you measured and proved there is something to gain. Everything else is either interesting history or an unnecessary bet.
On the sites we build all of this happens behind the scenes, without you having to think about it even once. If your site is slow because of images, or you are simply not sure what is going on there, reach us on WhatsApp through the site and we will take a look.