Image Formats Explained: The Complete Guide

You've got a photo that won't open. Or won't upload. Or takes up way too much space. And somewhere in the error message is a file extension you've never seen before.

This is the guide I wish existed when I started building CovertConvert. No fluff, no history lessons about formats invented in the 80s—just what each format actually does, when to use it, and how to convert between them.

The quick reference

Here's the cheat sheet. Bookmark this.

Format	Best for	Supports transparency	Lossy or lossless
JPG	Photos, sharing	No	Lossy
PNG	Screenshots, graphics	Yes	Lossless
HEIC	iPhone photos	Yes	Both
WebP	Web images	Yes	Both
AVIF	Next-gen web	Yes	Both
GIF	Simple animations	Yes (1-bit)	Lossless
TIFF	Print, archival	Yes	Both
BMP	Legacy Windows	No	Uncompressed

Now let's actually explain what all that means.

JPG (JPEG)

The format everyone knows. If you've ever saved a photo, you've probably used JPG.

What it is: A lossy format designed for photographs. "Lossy" means it throws away some data to make files smaller. You usually can't tell the difference.

Good for:

Sharing photos via email or messaging
Uploading to social media
Anything where file size matters more than perfect quality

Not good for:

Screenshots with text (gets blurry)
Graphics with sharp edges
Anything you'll edit multiple times (quality degrades each save)

The catch: No transparency support. Transparent areas become white or black.

→ Convert to JPG

PNG

The other format everyone knows. Screenshot something on any computer and you'll probably get a PNG.

What it is: A lossless format that preserves every pixel exactly. Files are bigger than JPG, but there's no quality loss.

Good for:

Screenshots
Logos and graphics
Anything with text
Images with transparency

Not good for:

Large photos (files get huge)
Situations where file size is critical

The tradeoff: Quality vs file size. PNG keeps everything, but you pay for it in megabytes.

→ Convert from PNG to JPG | Learn more: PNG vs JPG

HEIC

The format that made me build this site.

What it is: Apple's photo format, used by iPhones since 2017. Files are about half the size of JPG with the same (or better) quality.

Good for:

It's... not really your choice. Your iPhone just uses it.

The problem:

Windows won't open it natively
Half the websites reject it for uploads
Your parents definitely can't view it

What to do: Keep your photos as HEIC (it's actually better), and convert to JPG when you need to share with the non-Apple world.

→ Convert HEIC to JPG | Convert HEIC to PNG | Learn more: What is HEIC?

WebP

Google's answer to "JPG is old, can we do better?"

What it is: A modern format that can do both lossy (like JPG) and lossless (like PNG) compression, with smaller file sizes than both. Also supports transparency and animation.

Good for:

Websites (most modern browsers support it)
Replacing both JPG and PNG in many situations

The problem: You probably found this page because you downloaded an image from a website and now can't open it. WebP is great for the web, but older software doesn't support it.

→ Convert WebP to JPG | Convert WebP to PNG | Learn more: What is WebP?

AVIF

The new kid. Even newer than WebP.

What it is: Based on the AV1 video codec, AVIF offers the best compression ratios currently available. We're talking 50% smaller than JPG at the same quality.

Good for:

Bleeding-edge web development
Situations where every kilobyte matters

The problem: It's still so new (2019) that support is patchy. Even some modern apps can't open AVIF files.

→ Convert AVIF to JPG | Convert AVIF to PNG | Learn more: What is AVIF?

TIFF

The format professional photographers love and everyone else dreads receiving.

What it is: A flexible, high-quality format commonly used in photography, printing, and archiving. Can store massive amounts of image data.

Good for:

Professional photography workflows
Print production
Archival storage

The problem: Files are HUGE. Like, "why is this photo 50MB" huge. Also, most web services won't accept them.

What to do: If someone sends you a TIFF, convert it to JPG before trying to do anything with it. You'll thank yourself.

→ Convert TIFF to JPG | Convert TIFF to PNG | Learn more: What is TIFF?

GIF

Yes, like the animations. But also a legitimate image format from 1987 that refuses to die.

What it is: A format limited to 256 colors that supports simple animation and basic transparency.

Good for:

Simple animations (obviously)
Very simple graphics with few colors

Not good for:

Photos (256 colors isn't enough)
Anything with gradients
Modern use cases (WebP does everything GIF does, but better)

The catch: Converting to JPG or PNG loses the animation—you just get the first frame.

→ Convert GIF to JPG | Convert GIF to PNG | Learn more

BMP

A relic from the Windows 3.1 era that somehow still shows up.

What it is: Windows' original image format. Stores raw, uncompressed pixel data.

Good for:

Honestly? Not much anymore.

Why it still exists: Legacy software, old scanners with default settings, clipboard operations on Windows. You'll occasionally encounter BMP files and wonder where they came from.

The fix: Convert to JPG and the file will be 10-50x smaller with no visible quality loss.

→ Convert BMP to JPG | Convert BMP to PNG | Learn more

How to choose the right format

For photos you're sharing: JPG. Universal compatibility, good enough quality for most uses.

For screenshots or graphics: PNG. Text stays sharp, transparency works.

For web development: WebP if your audience's browsers support it, with JPG/PNG fallbacks.

For archival: TIFF or PNG for lossless, or the original format if it's already HEIC/AVIF.

For everything else: Convert to whatever the thing you're trying to use actually accepts.

The privacy thing

Quick note since you're probably here to convert something: most online converters upload your files to their servers. That means some company now has a copy of your photo.

I built CovertConvert specifically to avoid this. Everything runs in your browser—your files never leave your device. You can verify this by checking the Network tab in your browser's developer tools while converting.

Try it out if you've got files to convert.

Still confused?

If you're dealing with a specific format and this guide didn't cover your situation, check the blog:

Or just use the converter and let it figure out what your file is.