Image Converter Guide: How to Convert Image Formats Online (JPG, PNG, WebP, HEIC)

Oct 18, 2026

Image Converter Guide: How to Convert Image Formats Online (JPG, PNG, WebP, HEIC)

You download a photo and it will not open. You try to upload a picture to a form and it says "only JPG allowed". Your iPhone photo works on your phone but fails on a Windows laptop. All three problems have the same fix: an image converter. This guide explains what an image converter does, which format you should choose, and how to convert image format online for free using the ConvertLinx Image Converter, without uploading your files anywhere.

What Is an Image Converter?

An image converter (also called an image format converter, image type converter or photo format converter) changes a picture from one file type to another, for example PNG to JPG, JPG to WebP or HEIC to JPG. The picture looks the same, but the file is saved in a different format that another app, website or device can accept.

How to Convert Image Format Online in 3 Steps

  1. Open the free image converter
  2. Upload one or many pictures, then pick the new format (JPG, PNG or WebP are the most common)
  3. Adjust the quality slider if you want a smaller file, then download the result

The same steps work to change pic format on a phone, tablet or computer. No app, no signup and no watermark.

Which Image Format Should You Choose?

JPG (JPEG): the safest choice for photos. Almost every device, website and app accepts it, and the file size is small. The downside is that it does not support transparent backgrounds, and heavy compression can make details look blurry.

PNG: best for logos, icons, screenshots and anything that needs a transparent background. PNG is lossless, so the sharpness is kept, but the files are usually bigger than JPG.

WebP: a modern format made for websites. WebP files are commonly 25 to 35 percent smaller than JPG at similar quality, which helps pages load faster. Today all major browsers support it. Some older software and some upload forms still do not accept WebP, so convert it to JPG or PNG in that case.

HEIC: the format iPhones use for photos. It saves space, but Windows and many websites cannot open it without extra help. If you need to share or upload an iPhone photo, convert it to JPG first. We also wrote a step by step guide: how to convert HEIC to JPG free online.

GIF, BMP, ICO and SVG: GIF is for simple animations, BMP is uncompressed and very large, ICO is used for website favicons and SVG is a vector format that scales without losing sharpness.

Quick Comparison

  • Photos for sharing or forms: JPG
  • Logos, screenshots, transparent images: PNG
  • Website images and faster page speed: WebP
  • iPhone photos that must open on Windows: JPG
  • Favicons: ICO (or PNG, depending on the platform)

Common Conversions People Need

Convert a screenshot to JPG: screenshots are usually saved as PNG. Many portals accept only JPG, so upload the screenshot, choose JPG and download it. Lower the quality slider a little if the file is too large for the form.

Convert PNG to JPG: useful when you want a smaller file and do not need transparency. Try the dedicated PNG to JPG converter. Remember that transparent areas become a solid background in JPG.

Convert PNG or WebP for websites: converting large PNG photos to WebP is one of the easiest ways to reduce page weight. After converting, you can shrink the file further with the Image Compressor.

Convert JFIF to JPG: JFIF files are basically JPEGs saved with a different extension, and some apps refuse them. Use the JFIF to JPG converter to fix that.

Convert PNG to ICO: need a favicon for your website? Use the PNG to ICO converter.

Does Converting an Image Reduce Quality?

It depends on the target format. Converting to PNG does not lose quality, because PNG is lossless. Converting to JPG or WebP is lossy, so each save can remove a little detail. The ConvertLinx quality slider lets you choose how much to compress, from 50% to 100%. A common rule is to start around 80 to 90% for photos and only go lower if you really need a tiny file.

Two more points to remember. Format conversion keeps the original pixel size, so a 1080p photo stays 1080p. And converting does not upscale a low resolution picture to HD, it only changes the file type. If you need a different size, use the Image Resizer.

Why a Private, Browser Based Image Converter Is Safer

Many online converters upload your pictures to their server. That is a problem for ID cards, documents, family photos or client work. A browser based image converter runs the conversion inside your own browser, so your files never leave your device. The ConvertLinx image converter works this way, which makes it a private image converter you can use without worrying about who else sees your pictures.

Tips for Bulk Image Conversion

  • Select all your files together instead of converting one by one
  • Choose one target format for the whole batch, then use Download All
  • For large batches, convert in groups of 10 to 20 files so your browser stays fast
  • Keep your originals until you have checked the converted files

A Note About Supported Formats

The converter lists 22 formats to choose from. Browsers can natively save images as JPG, PNG and WebP, so these give the most reliable results. When you choose a format that your browser cannot encode directly, the tool saves a lossless PNG instead and tells you so. For everyday needs, JPG, PNG and WebP cover almost every case.

Frequently Asked Questions

Is the image converter really free? Yes. There is no signup, no watermark and no limit on how many pictures you convert.

Are my pictures uploaded to a server? No. Conversion happens in your browser, so your images stay on your device.

Can I convert iPhone HEIC photos? Yes. Upload the HEIC file, choose JPG or PNG and download it.

Can I convert many images at once? Yes. Select multiple files together and download the results one by one or with Download All.

Which format gives the smallest file? For websites, WebP usually gives the smallest file at good quality. For general sharing, JPG is a good balance.

Related Tools on ConvertLinx

Convert JPG, PNG, WebP and HEIC online — free, private, no signup, no watermark.

Convert Image Format Free →

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