WebP vs PNG vs JPG — Which Format Should You Use?
A no-fluff comparison of the three most common image formats. Learn when each format wins, typical file size differences, and how to convert between them in seconds.
The Short Answer
Use WebP for anything going on the web. Use PNG when you need transparency or pixel-perfect screenshots. Use JPG only when you need broad compatibility with legacy software or devices.
For everything else — read on. The right choice depends on your content, your audience, and where the image is going.
JPG — The Old Reliable
JPEG (Joint Photographic Experts Group) has been around since 1992. It uses lossy compression with a discrete cosine transform: at high quality settings (85–95%), the difference from the original is nearly invisible; at low settings, you see blocky artefacts, especially around sharp edges and text.
File size: Moderate. A typical photo at 85% quality is 200–500 KB.
Use JPG for:
- Photographs being sent to legacy devices or older email clients
- EXIF metadata workflows (cameras, printers, stock libraries)
- Any situation where the receiving system cannot handle WebP
Avoid JPG for: logos, illustrations, screenshots, anything with transparent areas (JPG has no alpha channel).
PNG — Lossless and Transparent
PNG (Portable Network Graphics) uses lossless compression. Every pixel you put in comes out exactly the same. It also supports an alpha channel, which means transparency down to individual pixels.
File size: Larger than JPG for photos. A photographic image saved as PNG is typically 3–5× the size of an equivalent JPG. For flat illustrations and screenshots, PNG is often more efficient than JPG because it handles solid-colour regions without artefacts.
Use PNG for:
- Logos and icons that need a transparent background
- UI screenshots (crisp text, hard edges)
- Source files you will edit again — no generation loss
- Illustrations with flat colours or limited palettes
Avoid PNG for: full-colour photographs on web pages — the file size penalty is severe.
WebP — The Modern Default
WebP was created by Google and released in 2010. It supports both lossy and lossless compression, as well as transparency (alpha channel) in both modes. The lossy codec is based on the VP8 video codec and typically produces files 25–35% smaller than JPEG at equivalent perceived quality.
Browser support: All modern browsers since around 2020. Chrome, Firefox, Safari (since 14), Edge, and Opera all support WebP natively. If you are targeting modern web audiences, compatibility is effectively universal.
Use WebP for:
- Web pages — photos, banners, product images, blog images
- Anything where you previously used PNG with transparency
- App assets targeting modern runtimes
Limitations: Not all desktop software opens WebP natively (though Windows 11, macOS 12+, and most image editors now support it). Raw file size savings over PNG for truly lossless content are modest.
AVIF — The Future (Almost Ready)
AVIF is based on the AV1 video codec and offers even better compression than WebP — typically 40–55% smaller than JPEG at equivalent quality. It supports HDR, wide colour gamuts, and transparency. Browser support reached mainstream in 2023 (Chrome 85+, Firefox 93+, Safari 16+).
The catch: encoding is slow. Generating AVIF images is 5–50× slower than JPEG or WebP, so it is not yet practical for user-upload workflows or real-time conversion. For pre-built assets, it is worth the one-time cost.
Side-by-Side Comparison
| Property | JPG | PNG | WebP | AVIF |
|---|---|---|---|---|
| Compression | Lossy | Lossless | Lossy / Lossless | Lossy / Lossless |
| Transparency | No | Yes | Yes | Yes |
| Photo file size vs JPG | Baseline | +200–400% | −25–35% | −40–55% |
| Browser support | Universal | Universal | All modern | Most modern |
| Encoding speed | Fast | Fast | Fast | Slow |
How to Convert Between Formats
The fastest way to convert images without installing anything is a browser-based tool. FileKit Image Converter converts between JPG, PNG, WebP, and AVIF in your browser — nothing gets uploaded. Drop your files, pick a format, adjust quality, and download.
For batch conversion in production, consider:
- Sharp (Node.js) — fast, excellent quality, supports all four formats
- ImageMagick — universal, works in shell scripts
- Squoosh CLI — great defaults, easy quality tuning
Practical Decision Guide
- Photo on a website? → WebP (with JPG fallback if you need IE11 support, which you almost certainly don't in 2025).
- Logo or icon with transparent background? → WebP (lossless mode) or PNG.
- Screenshot of software UI? → PNG. Lossless compression handles the hard edges and text better than any lossy format.
- Pre-built image assets for a performance-critical site? → AVIF with WebP fallback.
- Sending to someone who might open the file in Word or an older app? → JPG or PNG. Safest compatibility.