JPG vs PNG vs WebP: Which Image Format Should You Use?

By ImgCase Editorial Team · Updated 2026-10-04 · about 5 min read

Every image you save or share uses one of a handful of formats, and picking the wrong one costs you either file size or image quality. Here is a practical, jargon-light comparison of the three formats you meet every day — JPEG, PNG, and WebP — and a simple rule for choosing between them.

The quick answer

JPEG: the photo workhorse

JPEG (JPG) has been the default photo format since the 1990s. It uses lossy compression: some pixel data is discarded to shrink the file, trading a little fidelity for a much smaller size.

• Strengths: tiny files for photos, universally supported, adjustable quality.
• Weaknesses: no transparency, and quality drops each time you re-save — the classic “generational loss”.
• Use it for: photos destined for email, chat, and web pages where size matters more than pixel-perfect fidelity.

A good quality setting (75–90%) is visually indistinguishable from the original for most photos. Need a specific size cap? The Compress tool can hit a target like 200 KB automatically.

PNG: the lossless all-rounder

PNG uses lossless compression — every pixel comes back exactly as it went in. It also supports an alpha channel, meaning parts of the image can be fully or partially transparent.

• Strengths: pixel-perfect quality, transparency support, re-save without degradation.
• Weaknesses: large files for photos — often 5–10× bigger than an equivalent JPEG.
• Use it for: screenshots, UI captures, logos, anything with text or sharp edges, and anything needing a transparent background.

That “sharp edges” point matters: JPEG's compression tends to blur the transition between text and background, which is why JPG screenshots look muddy. PNG keeps every edge crisp.

WebP: the modern default

WebP (from Google) was built to combine the best of both worlds: lossy compression like JPEG at smaller sizes, plus transparency like PNG in the same file.

• Strengths: typically 25–35% smaller than JPEG at the same quality; supports transparency and animation.
• Weaknesses: some old software (very old browsers, certain editors) still does not open it.
• Use it for: website images — it is the best web default today.

For a website, WebP usually means faster page loads, better Core Web Vitals, and happier search rankings. All modern browsers support it, so the compatibility argument is mostly historical now.

A real-world size comparison

The same 1600×1200 photo, saved three ways at sensible settings:

Numbers vary by image, but the ratios hold: for photos, WebP wins on size, PNG wins on safety, JPEG wins on compatibility everywhere.

How to convert between them

You do not need desktop software to switch formats. The ImgCase Convert tool changes JPG, PNG, and WebP into each other entirely in your browser:

1. Drop your image onto the tool.
2. Pick JPEG, PNG, or WebP as the output.
3. Download the converted file — nothing is uploaded anywhere.

Converting to JPEG fills transparent areas with white automatically. Keep PNG or WebP if you need the transparency to survive.

Rules of thumb you can memorize

• Photo for the web → WebP
• Photo for a chat app that only accepts JPG → JPEG
• Screenshot, logo, or text-heavy image → PNG
• Anything with transparency → PNG or WebP, never JPEG
• Master copy you will edit again → PNG (lossless)

All ImgCase tools run in your browser — pick a tool and your files never leave your device.