Image Format Guide: JPG, PNG, WebP, AVIF, HEIC & ICO

By Nathan Hays · Updated July 28, 2026

Every image format is a trade-off between quality, file size, and compatibility. This guide explains what each one is best at. When you're ready, our free image converter switches between them instantly, right in your browser.

The formats at a glance

When to use each format

JPG: the everyday photo format

JPG (also written JPEG) is the default for photographs. It compresses colorful, detailed images into small files that open anywhere. The trade-off is that it's lossy (it discards some detail to save space) and it can't store transparency. For sharing photos by email or message, JPG is almost always the right choice.

Its real advantage is universality. JPG has been the standard photographic format for decades, which means every phone, camera, printer, operating system, upload form, and piece of software reads it without complaint. When you are handing a file to someone whose setup you cannot inspect, that matters more than any efficiency argument. Its weaknesses are equally consistent: hard edges pick up a faint halo, smooth gradients can band, and each re-save compounds the damage a little further. JPG vs PNG goes through those artifacts in detail.

PNG: sharp graphics and transparency

PNG is lossless, so it keeps every pixel exactly. That makes it ideal for logos, icons, screenshots, and anything with text or sharp edges, and it's the go-to when you need a transparent background. The downside is bigger files for full photographs.

PNG compresses by finding repetition, which is why a screenshot of an interface, full of flat color and repeated rows, can be remarkably small while a photograph of a forest is enormous. It is also the right working format: because it never degrades, you can open, edit, and re-save it indefinitely. Our PNG transparency guide explains how alpha channels behave and where they get lost.

WebP: the modern all-rounder

WebP does what JPG and PNG do, but with smaller files (typically 25–35% smaller at the same quality), and it supports transparency. It's now supported by every major browser, which makes it excellent for websites where speed matters.

It is effectively two formats in one: a lossy mode for photographs and a lossless mode for graphics, both able to carry transparency. That is why it can replace JPG and PNG rather than just one of them. Support outside the browser is thinner, which is the one thing to keep in mind before sending a WebP to another person. WebP explained covers the savings and the caveats.

AVIF: the smallest files

AVIF is the newest format here and usually produces the smallest files of all, even beating WebP, while supporting transparency and a wider range of color. It takes a little longer to create and isn't supported by some older software, so it's best for modern websites.

Because AVIF is so efficient, many sites now serve it by default, which is why a picture you save from the web sometimes arrives as a .avif file that your photo editor refuses to open. Your browser reads it perfectly well, so converting AVIF to JPG takes seconds and makes the image universal again.

HEIC: the iPhone format

HEIC is what iPhones use to store photos, and it's very space-efficient. The catch is compatibility: many websites, apps, and Windows PCs can't open HEIC files. The usual fix is to convert HEIC to JPG (or PNG) so the photo works everywhere. Our converter does this on your device, so your photos stay private.

HEIC stores a photograph in roughly half the space of a comparable JPG and can hold extra data alongside the picture, which is how Live Photos and depth effects travel with the file. Converting produces a still image without that extra data. What is HEIC covers why Apple chose it and how to stop your phone creating them if you would rather not deal with it.

ICO: website favicons

ICO is the format for the little icon in a browser tab: the favicon. An ICO file can hold several sizes at once, so the browser always has a crisp version. To make one, convert a square PNG to ICO and the converter builds a multi-size file for you.

The file this converter produces contains 16, 32, 48, and 256 pixel versions, with transparency preserved. Start from a square source if you can; a non-square image is scaled to fit and centered, leaving transparent space around it. Simple, high-contrast artwork survives being shrunk to 16 pixels, while a detailed logo turns to mush at that size.

Lossy vs lossless: what it means for quality

Lossless formats (PNG, and lossless WebP) preserve the image perfectly. Lossy formats (JPG, and lossy WebP/AVIF) throw away some detail to shrink the file. At high quality the loss is usually invisible, but repeatedly re-saving a lossy image can slowly degrade it. When quality matters and file size doesn't, choose a lossless format; when you need small files, a lossy format with a high quality setting is the sweet spot.

Two practical consequences follow. First, converting between lossy formats always costs a little, because the picture is decoded and encoded again; at 90% quality the cost is invisible, but stacking half a dozen such conversions is not. Second, converting to a lossless format never improves anything. It freezes the image where it is, which is useful before an edit and useless as a repair for a photo that already looks soft.

Choosing by job, not by format

The fastest way to decide is to start from where the image is going rather than from what it is.

• Emailing a photo: JPG at 80 to 85% quality. It opens everywhere and stays under attachment limits.
• A photo on a website you run: WebP, or AVIF for the images that matter most.
• A screenshot of text or code: PNG, always. JPG smears small letterforms.
• A logo that must sit on any background: PNG, or lossless WebP if the destination supports it.
• Printing: a high-quality JPG at the largest dimensions you have. Do not downscale.
• An upload form that keeps refusing your file: JPG or PNG, and lower the quality if there is a size cap.
• A browser tab icon: ICO, made from a square PNG.

Our guide to converting for email, web, print, and social works through each destination in more depth, and image size vs quality explains which lever to pull when a file is simply too big.

What conversion cannot do

Conversion changes how a picture is stored, not what is in it. It is worth being clear about the limits, because they account for most of the disappointment people run into:

• It cannot restore lost detail. Converting a heavily compressed JPG to PNG preserves it perfectly as it is; it does not sharpen or repair it.
• It cannot create transparency. A photograph converted to PNG is still an opaque photograph. Removing a background is an editing job.
• It cannot keep animation. All the output formats here are still images, so an animated GIF becomes a single frame.
• It does not resize. The converted file has exactly the pixel dimensions of the original.
• It does not carry metadata across. EXIF details, including any GPS location, are left behind, which is usually a benefit. See image metadata and EXIF.

Frequently asked questions

More guides

• JPG vs PNG: when each format wins
• WebP explained: savings and compatibility
• What is HEIC, and how to share iPhone photos
• PNG transparency: alpha channels and white boxes
• Image size vs quality: what actually shrinks a file
• Converting for email, web, print, and social
• Image metadata and EXIF
• Convert HEIC to JPG (iPhone photos)
• PNG to ICO favicon converter
• WebP to JPG converter
• PNG to JPG converter
• JPG to PNG converter
• AVIF to JPG converter
• HEIC to PNG converter
• JPG to WebP converter
• Image Converter FAQ
• All guides and converters