Convert your images online

Directly in your browser, with no transfer to a server.

How to convert your images

Three steps to change your file format.

1

Add your images

Drag and drop or select your files from your device.

2

Choose the output format

Select JPG, PNG, WebP, AVIF, JPEG XL or PDF. Adjust quality if needed.

3

Download the result

Download converted files individually or together in a ZIP archive.

Image converter in your browser

Change your file format without uploading to a server. Choose the quality and output format, then download the result as a ZIP.

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Input formats

Convert the most common image formats, including iPhone photos.

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Output format

Choose the right format: JPG, PNG, WebP, AVIF, JPEG XL or PDF.

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Batch processing

Convert several images and download files separately or as a group.

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Local processing

Conversion in your browser. Nothing is sent to a server.

Frequently asked questions

How do I convert an image with Constelly? expand_more

Add your images to the tool, choose the desired output format — JPG, PNG, WebP, AVIF, JPEG XL or PDF — then start the conversion. You can download each file separately or get the whole batch in one ZIP archive.

Are my images sent to a server? expand_more

No. Your images are converted directly in your browser. They stay on your device and are not sent to our servers during the process.

Which file formats are supported? expand_more

You can import JPG, PNG, WebP, AVIF, HEIC, HEIF and TIFF images. Then choose an output format: JPG, PNG, WebP, AVIF, JPEG XL or PDF.

Can I convert multiple images at once? expand_more

Yes. Add several files at once, choose a common output format, and start the conversion. Download images one by one or get all results in a ZIP archive.

Which output format should I choose? expand_more

JPG is the most compatible choice and works almost everywhere. PNG is useful when you need a common, reusable image file. WebP and AVIF are often lighter for the web. JPEG XL can preserve high image quality. PDF lets you combine several images in one document.

Why is my converted file sometimes larger? expand_more

That is perfectly normal. Conversion does not always reduce an image's size; its main purpose is to change the format. Some formats, such as WebP or HEIC, are very efficient and can be smaller than PNG or JPG. Converting to a more compatible or less compressed format can therefore create a larger file. The displayed size is simply information to help you choose.

Does conversion reduce image quality? expand_more

Not necessarily. It depends on the selected format. Some formats, such as JPG, recompress the image to make it easier to share. When a quality setting is available, values closer to 100% keep the result closer to the original. To preserve the original as much as possible, choose PNG or JPEG XL.

Can I convert iPhone photos (HEIC)? expand_more

Yes. HEIC and HEIF photos from an iPhone are supported. Convert them to JPG, PNG, WebP or AVIF to open, email or publish them more easily.

Can I convert TIFF files? expand_more

Yes. TIFF files are supported. They can be very large, so conversion may take longer on less powerful computers. Because processing happens in your browser, performance mainly depends on your device.

Can I combine several images into one PDF? expand_more

Yes. Choose PDF as the output format. Imported images will be combined into one document in the order they were added.

Do I need an account? expand_more

No. You can convert images without signing up. Pro access is only for regular use or larger batches.

Does the tool work offline? expand_more

Yes, once the page has loaded. You need internet to open the tool, but conversion itself can happen without sending files online.

What file size is recommended? expand_more

For a smooth experience, files under 30 MB are most comfortable. Larger images may also work, but conversion can take longer depending on your computer.

Is image conversion free?expand_more

Yes, image conversion is free and requires no sign-up. To process large volumes or use it regularly, switch to Pro.

When should you convert an image?

Changing formats is useful in many everyday situations.

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iPhone photos (HEIC)

iPhones save photos as HEIC, a format that Windows and many websites cannot open. Convert them to JPG to share them anywhere.

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Modern web formats

WebP and AVIF are much lighter than JPG or PNG. They are ideal for a fast-loading website without sacrificing quality.

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Meet a required format

Does a website, app or form accept only a specific format? Convert your image in seconds.

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Standardize a photo batch

Files in different formats? Convert them all to the same format in one go.

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Your images never leave your computer

Most online converters upload photos to their servers. Not here. Conversion happens in your browser: your images stay with you, and nothing is transferred or stored.

cloud_off Nothing is uploaded
lock Nothing is stored
person_off No sign-up required

Does conversion damage the image?

It depends on the selected format. Converting to lossless PNG or WebP preserves the original image exactly. JPG and AVIF compress slightly to reduce file size, with a quality setting you control. Choose the balance between size and fidelity that suits you.

Which output format should you choose?

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JPG

The universal format. Readable everywhere and perfect for emailing a photo or sending it to a client.

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WebP

Lighter than JPG at the same quality. The best choice for images on a modern website.

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AVIF

Even lighter and next-generation. Ideal for the web when size matters, if your tools support it.