Reference

Image File Format Guide

Every image format is a trade-off between file size, quality, and how many programs can open it. These guides explain what each format actually does, the mistakes that cost people quality, and which format to convert to for the job in front of you.

Everyday web and photo formats

JPG What is a JPG file? JPG — also written JPEG — is the most widely used photographic image format in the world. Here is how its compression actually works, the one mistake that quietly ruins photos, and when a modern format will serve you better. PNG What is a PNG file? PNG is the web's lossless format — the one that never degrades and the one that handles transparency properly. It is also the format people most often use for the wrong job, producing files ten times bigger than they need to be. WebP What is a WebP file? WebP is Google's replacement for JPEG and PNG at once — smaller than both, with transparency and animation built in. It is also the format most likely to be sitting in your downloads folder refusing to open in an older program. AVIF What is an AVIF file? AVIF is currently the most efficient image format in mainstream use — routinely half the size of a JPEG at the same visual quality, with HDR and transparency included. The catch is that it is slow to create and not yet universally readable. GIF What is a GIF file? GIF has outlived nearly every format of its generation on the strength of one feature — animation that plays anywhere without a video player. Technically it has been obsolete for years, and understanding why explains most of its quirks.

Vector and specialist formats

SVG What is an SVG file? An SVG is not a picture — it is a set of drawing instructions. That single difference is why an SVG logo stays razor sharp at any size, why you can edit one in a text editor, and why it is a poor fit for photographs. ICO What is an ICO file? ICO is not really an image format — it is a container that holds several images at once. That design comes straight from Windows 1.0, and it is the reason ICO is still the safe answer for a favicon four decades later. EPS What is an EPS file? EPS is a print-era vector format built on PostScript, the page description language that drove the desktop publishing revolution. It is largely superseded, but print suppliers still request it, and knowing why explains how to handle one. PSD What is a PSD file? A PSD is a working file, not a delivery file. It preserves every layer, mask, and adjustment so you can change your mind later — which is exactly why it is the wrong thing to send to anyone who just needs the picture. JXL What is a JXL file? JPEG XL is technically the most complete image format anyone has shipped — excellent lossy compression, genuinely good lossless compression, and a migration path that shrinks existing JPEGs without touching their quality. Its problem has never been the technology.

Phone, scanner and archive formats

HEIC What is a HEIC file? HEIC is the format your iPhone photos are stored in. It is roughly half the size of the equivalent JPEG at the same quality — and it is the single most common reason people find themselves looking for a file converter. TIFF What is a TIFF file? TIFF is the format archives, scanners, and print workflows have trusted for nearly four decades. It is extraordinarily flexible — so flexible that two files with the same extension can have almost nothing in common. BMP What is a BMP file? BMP is about as simple as an image format gets: a small header followed by the colour of every pixel, one after another. That simplicity made it the Windows standard for years, and it is also why a BMP is enormous.

Camera RAW formats

RAW What is a RAW file? A RAW file is not a photograph — it is the unprocessed measurement your camera's sensor made. Understanding that distinction explains why RAW files look flat, why every program renders them slightly differently, and why they cannot simply be displayed like a JPEG. CR2 What is a CR2 file? CR2 is Canon's RAW format from the era of the 20D through to the mid-2010s. It sits between the older CRW and the current CR3, and the three are different enough that software supporting one may well refuse the others. NEF What is a NEF file? NEF is Nikon's RAW format, in use since 1999 and still current. It is one of the better-behaved RAW formats — broadly supported and reasonably stable across camera generations — with a few settings that quietly affect what you get. ARW What is an ARW file? ARW is Sony's RAW format, inherited from Minolta when Sony acquired its camera division and used across the Alpha line ever since. Its one notable quirk is a compression setting that was, for years, not optional. DNG What is a DNG file? DNG is Adobe's attempt to fix the central problem with camera RAW: that every manufacturer invented its own undocumented format, and none of them promised to keep it readable. It is published, open, and the closest thing RAW has to a standard.

Convert between any of them

Zolvo's image converter handles every format on this page — JPG, PNG, WebP, AVIF, HEIC, SVG, TIFF and camera RAW — entirely inside your browser. Nothing is uploaded to a server, and there is no sign-up or file-size limit.

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