Image Converter: How It Works and Which Format to Choose
Short answer
An image converter changes a picture from one file format to another, for example HEIC to JPG or PNG to WEBP, so it opens where you need it or loads faster. Use JPG for photos, PNG for logos and screenshots that need sharp edges or transparency, and WEBP or AVIF for the smallest website images. Converting a lossless file never loses detail; converting between lossy formats can lower quality a little.
- JPG: best for photos, opens everywhere, no transparency
- PNG: lossless, supports transparency, larger files
- WEBP: smaller than JPG and PNG, supports transparency
- AVIF: often the smallest, newer software only
- HEIC: iPhone default, convert to JPG to share
What is an image converter?
An image converter is a tool that reads a picture in one format and saves it in another. People use one when a website rejects their file type, when a photo from an iPhone will not open on a Windows PC, or when they want smaller images for a web page. A good converter also keeps transparency where the new format allows it and does not change the picture size unless you ask.
How do I convert an image online?
- Open the online image converter and add your image.
- Select the format you need, for example JPG, PNG or WEBP.
- Click Convert.
- Download the result. Several files can be downloaded together as a ZIP.
JPG vs PNG vs WEBP vs AVIF vs HEIC: which should I use?
| Format | Compression | Transparency | Best for | Works everywhere? |
|---|---|---|---|---|
| JPG | Lossy | No | Photos, email, social media | Yes |
| PNG | Lossless | Yes | Logos, screenshots, icons | Yes |
| WEBP | Lossy or lossless | Yes | Fast website images | Modern browsers and apps |
| AVIF | Lossy or lossless | Yes | Smallest web images | Newer software only |
| HEIC | Lossy | Yes | Saving space on iPhone | Mostly Apple devices |
A simple rule: choose JPG when you need it to open anywhere, PNG when you need exact pixels or transparency, and WEBP when you care about page speed.
Does converting an image reduce quality?
- Lossless to lossless (for example PNG to TIFF): no loss, the pixels are identical.
- Lossless to lossy (PNG to JPG): a small, normally invisible loss, in exchange for a smaller file.
- Lossy to lossy (JPG to WEBP): the picture is compressed a second time, so convert from your original file when you can.
- Lossy to lossless (JPG to PNG): no new loss, but the file gets larger and the detail already thrown away does not come back.
What happens to transparent backgrounds?
JPG, BMP and PDF cannot store transparency, so transparent areas turn white when you convert to them. PNG, WEBP, AVIF, GIF and TIFF keep it. If you need a logo with a see-through background, convert to PNG or WEBP.
How do I make images smaller?
There are two levers: the format and the size. Switching a photo from PNG to WEBP or JPG usually saves the most. After that, use the Resize option to reduce the pixel dimensions and the Compress slider to lower the quality a little. Tick Keep original format if you want the file to stay a JPG or PNG.
Can an image converter make PDFs?
Yes. Choose PDF as the output format to turn a picture into a PDF page, or combine many pictures into one document. Our step-by-step guide covers it: how to convert an image to PDF.
Frequently asked questions
What is the best image converter?
The best one is free, needs no signup, keeps quality, handles many formats and deletes your files quickly. EasyImageConvert is built around those points.
How do I convert HEIC to JPG?
Upload the HEIC photo, choose JPG and click Convert. The JPG opens on any phone, computer or website.
Is JPG or PNG better?
JPG is better for photos because the files are smaller. PNG is better for logos, text and screenshots because it is lossless and supports transparency.
Is WEBP better than JPG?
For websites, usually yes: WEBP is typically smaller at similar quality. JPG is still the safer choice when the file has to open in every program.
Will my image lose quality when I convert it?
Not if you convert between lossless formats. Converting to a lossy format such as JPG or WEBP trades a small amount of detail for a smaller file.
Can I convert many images at once?
Yes. You can add up to 20 images, convert them together and download them as one ZIP.
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