If your images are still JPG and PNG, you’re shipping files that are 25–50% bigger than they need to be. Modern formats — WebP and AVIF — were designed to fix exactly that: same picture, far smaller file, full browser support. This guide explains which to use, when each wins, and how to convert in bulk without uploading anything.
TL;DR — Use WebP as your default (smaller than JPG/PNG, works everywhere). Use AVIF when you want the smallest possible file and can accept slower encoding. Convert a whole folder for free in the bulk image converter.
Why WebP and AVIF beat JPG and PNG
JPG (1992) and PNG (1996) are old. The formats that replaced them are smarter about how they store an image.
| Format | Typical size vs JPG | Transparency | Browser support | Best for |
|---|---|---|---|---|
| JPG | baseline | No | Universal | Legacy compatibility |
| PNG | larger | Yes | Universal | Graphics, transparency |
| WebP | −25 to −35% | Yes | All modern browsers | Default web format |
| AVIF | −40 to −50% | Yes | All modern (newer) | Smallest possible size |
The savings compound across a page. Convert a gallery of 30 photos from JPG to WebP and you can shave megabytes off the total — which directly improves load time and Core Web Vitals.
When to use WebP
WebP is the safe default for almost everything on the web:
- Photographs — lossy WebP at quality 80 looks identical to JPG but is meaningfully smaller.
- Graphics with transparency — lossless WebP replaces PNG at a fraction of the size.
- Anything you want to “just work” — every current browser renders it without a fallback.
When to use AVIF
Reach for AVIF when size is the top priority and you control the publishing pipeline:
- Large hero images where every kilobyte counts.
- Image-heavy pages (galleries, catalogues, portfolios).
- HDR or wide-gamut photography, which AVIF preserves better.
The trade-off: AVIF encodes more slowly, and you may want a WebP fallback for the oldest browsers in your audience.
Tip: You don’t have to choose globally. Use AVIF for your big hero shots and WebP for everything else. Both convert from the same source in seconds.
Step by step: convert images to WebP or AVIF
- Gather your source files — JPG, PNG, or even existing WebP/AVIF.
- Open the bulk image converter and drop them all in.
- Choose the target format — WebP or AVIF.
- Set the quality for lossy output (80 is a great starting point) or pick lossless for graphics.
- Download the converted images individually, or the whole batch as a zip.
It all runs in your browser, so there’s no upload, no sign-up, and no size limit from us. Your images never touch a server.
A note on quality
Converting format and compressing are two sides of the same coin. For the cleanest result:
- Start at quality 80 and compare to the original at full size.
- For logos, icons and screenshots with text, prefer lossless to keep edges crisp.
- Resize the image to its display size first — there’s no point encoding pixels nobody will see.
For a deeper dive on settings, read how to compress images without losing quality.
Where to go next
- Compress images without losing quality — get the quality settings right.
- Resize images for the web — the step most people skip.
- Remove an image background for free — then export as transparent WebP or PNG.