How to Convert Images Online Free: WebP, PNG, JPG, AVIF & HEIC (2026)

You can't upload a WebP to a site that only takes JPG, and you can't open a HEIC from your iPhone on half of Windows apps. Converting between image formats is one of those small, constant tasks — and most online converters make you upload private photos to a server to do it.

The free Image Converter on ZeroTools converts between JPG, PNG, WebP, AVIF, and HEIC entirely in your browser, in batches, with quality and resize controls — and downloads multiple files as a ZIP. Nothing is uploaded. This guide covers how to convert and, just as important, which format to convert to.

Key Takeaways

• Convert JPG, PNG, WebP, AVIF, and HEIC in any direction, one file or many at once.
• WebP files are typically 25–34% smaller than JPEG at equivalent quality, and 26% smaller than PNG losslessly (Google).
• Choose JPG for universal compatibility, WebP/AVIF for the smallest web files, PNG for transparency.
• Everything runs locally in your browser — your images never leave your device, even in batch.

Which Image Format Should You Convert To?

The right target format depends on where the image is going. The modern formats — WebP and AVIF — produce much smaller files, which speeds up page loads and helps SEO, but older software may not open them. JPG remains the universal fallback that opens everywhere.

Format	Strength	Convert to it when
JPG	Universal compatibility	You need a file that opens anywhere — email, print, old apps
PNG	Lossless + transparency	You need a transparent background or crisp graphics/text
WebP	Small files, wide support	Publishing to the web — best size-to-compatibility balance
AVIF	Smallest files	Maximum compression on modern browsers
HEIC	iPhone default	(Convert away from it) for compatibility on Windows and the web

For a deeper comparison of when each format wins on quality, size, and SEO, see the guide to WebP vs PNG vs JPEG. If you're specifically dealing with iPhone photos, the HEIC to JPG guide covers that case in detail.

How to Convert an Image: Step-by-Step

Open the Image Converter and follow these steps. You can convert a single image or a whole batch in one go.

Step 1: Add Your Images

Drag one or more images onto the drop zone, or click to browse. It accepts JPG, PNG, WebP, AVIF, and HEIC/HEIF. Add as many as you like — they queue up with thumbnails, and HEIC files are decoded automatically so you can see a preview.

Step 2: Choose Format, Quality, and Size

Pick your target format from the dropdown: JPG, PNG, WebP, or AVIF. For the lossy formats, a Quality slider (10–100%) controls the size-versus-detail trade-off — 90% is a good default. The Max Width option can downscale large images to 1920px, 1080px, or 800px while converting, which is handy for getting web-ready sizes in one step.

Step 3: Convert and Download

Click Convert All. Each image processes in turn, showing its new size. Then click Download — a single image downloads directly, while a batch is packaged into a ZIP automatically. The whole process runs on the Canvas API in your browser, so even large batches never touch a server.

Converting WebP to JPG (and Back)

WebP to JPG is one of the most common conversions, because many websites and downloads now serve WebP that older editors, email clients, and print services can't open. To convert, add your WebP file, choose JPG as the target format, and download. The reverse — JPG to WebP — is the move when you're optimising images for your own website and want smaller files.

One thing to know: converting to JPG or any non-PNG format fills transparency with a white background, since JPG can't store transparency. If your image has a transparent background you want to keep, convert to PNG or WebP instead. If you also need to shrink the result further, run it through the Image Compressor afterward.

Is It Private? Yes — No Uploads

Photos are personal. Converting them through a server means handing your images to a third party, even temporarily. This converter uses your browser's built-in Canvas API to do the work locally — your images are never uploaded, stored, or seen by anyone. Even a 50-file batch is processed entirely on your device.

That makes it safe for private photos, screenshots with sensitive information, and client work under NDA. For a broader look at why local tools beat upload-based ones, see the guide to free online tools that don't upload your files.

Convert Your Images Now

Open the free Image Converter, drop in your files, pick a format and quality, and download — single file or ZIP. No signup, no upload, no watermark, no limit on how many you convert.

To finish the job, pair it with the Image Compressor to shrink files further and the Image Cropper to reframe them. The WebP vs PNG vs JPEG guide helps you pick the best format for each use.

Frequently Asked Questions

How do I convert WebP to JPG for free?

Open the Image Converter, drag in your WebP file, choose JPG as the target format, and click Convert All, then Download. It runs in your browser with no upload, no watermark, and no limit. The conversion fills any transparency with white, since JPG can't store a transparent background.

Can I convert multiple images at once?

Yes. Drop in as many images as you like and they queue with thumbnails. Click Convert All to process the whole batch in one go, then Download — a single file saves directly, while multiple files are packaged into a ZIP automatically. There's no enforced limit on batch size.

What format should I convert my images to?

Use JPG for universal compatibility, PNG when you need transparency or crisp graphics, and WebP or AVIF for the smallest web files. WebP is typically 25–34% smaller than JPEG at the same quality (Google), making it the best balance of size and browser support for the web.

Does converting an image reduce its quality?

It depends on the format. PNG is lossless, so converting to PNG keeps full quality. JPG, WebP, and AVIF are lossy — the Quality slider controls how much detail is kept. At 90% quality the loss is generally invisible, while lower settings trade detail for a smaller file.

Are my images uploaded to a server?

No. All conversion happens locally in your browser using the Canvas API. Your images are never uploaded, stored, or transmitted, even when converting a large batch. This makes it safe for private photos and sensitive screenshots, and it works offline once the page has loaded.