How to use it
- 1.Pick the format you need under “Convert to”: JPG for photos that must open anywhere, PNG for graphics and screenshots, WebP or AVIF for small files on websites.
- 2.Drop your images on the page, paste one from the clipboard, or click “Choose images”. You can add many at once.
- 3.Each image is converted as soon as it’s added. Change the format or quality and the whole list is converted again.
- 4.Download images one by one, or all of them as a ZIP file.
Which format to choose
JPG is the safe choice for photos: every device, app and website accepts it. It has no transparency, so transparent areas are filled with the background colour you pick.
PNG stores every pixel exactly (lossless) and keeps transparency. It suits logos, screenshots, diagrams and images with text, but photos saved as PNG are many times larger than as JPG.
WebP makes files about 25–35 % smaller than JPG at the same visual quality and supports transparency. All current browsers show it, which makes it a good default for websites. AVIF goes further, often half the size of JPG, but takes longer to create and some older software can’t open it.
Converting iPhone HEIC photos
iPhones save photos as HEIC (High Efficiency Image Container) to save space. Windows, many websites and older apps can’t open them. Convert them to JPG here and they open everywhere.
To stop your iPhone creating HEIC files, go to Settings → Camera → Formats and choose “Most Compatible”. When you share photos from an iPhone, they are usually converted to JPG automatically; the HEIC originals appear when you copy files directly from the phone to a computer.
What quality to use
For JPG, WebP and AVIF the quality setting trades detail for file size. Around 85 is hard to tell apart from the original; 70–80 suits web pages; below 60 artefacts appear around edges and in skies. PNG ignores the setting because it’s always lossless.
Converting a JPG to PNG doesn’t bring back detail the JPG already lost; it only makes the file larger. Convert from the best original you have. Converted files don’t carry over the camera metadata (EXIF), including any GPS location.
Questions and answers
Are my images uploaded to a server?
No. The images are decoded and encoded by your browser on your own device, using the same open-source codecs as Google’s Squoosh. Nothing is sent to nestoo or anyone else, and the tool keeps working offline once the page has loaded.
How do I convert HEIC to JPG?
Choose JPG under “Convert to”, then drop your HEIC photos on the page. Each one is converted to JPG right away; download them one by one or all together as a ZIP.
Can I convert several images at once?
Yes. Add as many images as you like; they are converted one after another, and “Download all as ZIP” saves them in a single file. Very large photos take a moment each, especially when converting to AVIF.
Will converting keep transparency?
PNG, WebP and AVIF keep transparent areas. JPG can’t store transparency, so transparent pixels are filled with the background colour (white unless you pick another).
Why is my converted file bigger than the original?
Converting a compressed photo to PNG, or to JPG at a higher quality than the original used, produces a larger file without adding any detail. Pick WebP or AVIF, or lower the quality, to get a smaller file. To shrink images without changing their format, use the image compressor.