JPG vs PNG vs WebP: which image format should you use?

Choosing between JPG, PNG and WebP comes down to what’s in the image and where it’s going. In short: use JPG for photos that need to open anywhere, PNG for transparent backgrounds and sharp text or charts, and WebP (or AVIF) to make images on web pages lighter. If you don’t know which formats the recipient supports, JPG is the safest choice.

The formats at a glance

Feature	JPG	PNG	WebP	AVIF
Compression	Lossy	Lossless	Lossy or lossless	Lossy or lossless
Transparency	No	Yes	Yes	Yes
Animation	No	Yes, as APNG	Yes	Yes
Typical use	Photos, email attachments	Logos, screenshots, charts	Images on web pages	Images on web pages

This table is based on MDN’s image format guide.

JPG vs PNG: photos, or transparency and text?

JPG

JPG (JPEG) uses lossy compression and is built for photos. MDN describes it as a good choice for lossy compression of still images and the most popular format today. Every major browser supports it, so it’s the natural pick when you email or submit photos.

Its weak spot is transparency: JPG can’t store it. When you convert a transparent PNG to JPG, the transparent areas have to be filled with a color. Our test PNG (800×600 with a transparent background, 204 KB) became a 16 KB JPG at quality 85, with the transparent areas filled with white. Measured in desktop Chrome; results vary by device and browser.

PNG

PNG uses lossless compression, and the W3C PNG specification includes an optional alpha channel for transparency. MDN says PNG is preferred over JPEG when you need a more precise copy of the source image or when you need transparency. That makes it a good fit for logos, icons, screenshots and charts.

The flip side: saving a photo as PNG makes the file much larger. Our 4000×3000 test JPG (4.0 MB) became a 10.9 MB PNG, and an 800×600 JPG (49 KB) became 398 KB. Measured in desktop Chrome; results vary by device and browser. Converting a JPG to PNG also won’t bring back detail that changed when it was saved as JPG. It only stops the quality from dropping any further.

PNG files can get lighter with fewer colors, too. The PNG specification defines indexed color with a palette of 1 to 256 entries, and the Reduce colors option in Compress Image uses it to bring an image down to 256 colors or fewer.

WebP and AVIF: lighter images for the web

WebP supports lossy and lossless compression, transparency and animation. Google says lossless WebP images are 26% smaller than PNGs, and lossy WebP images are 25–34% smaller than comparable JPEGs at the same SSIM quality index. Chrome, Safari, Firefox, Edge and Opera support it natively.

AVIF also supports lossy and lossless compression, transparency and animation, and MDN says it compresses much better than PNG or JPEG. Browser support starts at Chrome 85, Firefox 93, Safari 16.1 and Edge 121, so MDN recommends adding a fallback in a more widely supported format when you use AVIF.

Converting our 4000×3000 test JPG (4.0 MB) at the default quality gave 1.8 MB as WebP (quality 85) and 532 KB as AVIF (quality 60). Measured in desktop Chrome; results vary by device and browser. These formats work well on web pages, but AVIF may not open in older programs or browsers. For email attachments or submissions, check which formats the recipient supports first.

GIF, often used for animations, is limited to a palette of up to 256 colors. MDN suggests PNG for still images and WebP, AVIF or APNG for animations.

Which format for which job

Situation	Best format
Emailing, messaging or submitting photos	JPG
Logos and icons that need a transparent background	PNG (or WebP for the web)
Screenshots and charts with lots of text	PNG
Photos for a blog or web page	WebP or AVIF, with a JPG fallback
Sending iPhone HEIC photos to other devices	Convert to JPG

What about iPhone HEIC photos?

When the iPhone camera format is set to High Efficiency, photos are saved as HEIF (High Efficiency Image File Format). Apple says HEIF compresses better than JPEG, so it uses less storage while keeping the same visual quality. The catch is that devices and services without HEIF support may not open these files. Convert them to JPG before you send or submit them. See 3 ways to convert iPhone HEIC photos to JPG for your options.

How to do it with ZEKILO Studio

1. Open Image Converter and drag and drop images or pick them with [Choose files]. Conversion starts as soon as they’re added.
2. Under [Convert to], pick JPG (default), PNG, WebP or AVIF, and adjust [Quality] if needed (defaults: 85 for JPG and WebP, 60 for AVIF). When converting to JPG, choose [White], [Black] or [Custom] under [Fill transparent areas].
3. Save with [Download]. For several images, use [Download all (ZIP)] to get them in one go.

Conversion happens inside your browser, and files never leave your device. For animated GIF and WebP, only the first frame is converted. To shrink files without changing the format, use Compress Image. If you only need to turn iPhone photos into JPG, use HEIC to JPG.

Summary

• JPG is for photos. It opens anywhere but can’t store transparency.
• PNG is for transparency, text and charts. Photos get much larger as PNG.
• WebP and AVIF make images on web pages lighter. Check that the recipient supports them.
• Convert iPhone HEIC photos to JPG before you send or submit them.