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You downloaded a picture and it is a WebP. The form you need to upload it to says “JPG or PNG only”. You rename the file to .jpg, it fails, and now you are wondering what is actually different between these formats and why renaming does not work.
The Image Converter turns a picture into JPG, PNG or WebP, shows the size before and after, and keeps the width and height exactly as they were. This guide explains what each format is good at, what really changes when you convert, and how to avoid the common traps.
Three formats, three jobs
| JPG | PNG | WebP | |
|---|---|---|---|
| Best for | Photographs | Logos, screenshots, graphics, text on images | Websites that want small files |
| Quality | Lossy: a little detail is discarded | Lossless: every pixel is kept | Can be either, depending on the setting |
| Transparency | No | Yes | Yes |
| File size for a photo | Small | Large | Smallest |
| Accepted by old software and upload forms | Almost always | Almost always | Often not |
WebP is supported by all current major browsers, but many forms and older programs were written before it existed, which is why they ask for JPG or PNG.
The difference comes down to how each format stores the picture. JPG looks for detail the eye hardly notices, such as tiny colour changes, and drops it. That is why photos shrink so well and why a JPG of a logo looks slightly smudged around the edges. PNG keeps every pixel exactly, which suits flat colours and sharp lines but makes a photograph many times bigger. WebP uses more modern tricks to get smaller files than either.
How to convert, step by step
- 1Add the pictureChoose a JPG, PNG or WebP file. The tool shows a preview and its current size.
- 2Choose the formatPick JPG, PNG or WebP as the format you want.
- 3Set the quality (JPG and WebP only)A slider from 10 to 100, set to 90 by default. PNG has no quality setting because it keeps everything.
- 4Convert and downloadThe new file keeps the same name with a new ending, such as
photo.jpg, and shows its size.
The width and height stay the same. If you also need a different size, resize afterwards with the Image Resizer.
The converter handles one picture at a time. For a whole batch of iPhone photos, use the HEIC to JPG Converter, which can convert many at once.
What happens to the file size
Converting does not always make a file smaller. It depends on what you start with and where you end up.
| Conversion | Usual effect on size | Quality effect | Worth doing? |
|---|---|---|---|
| PNG photo to JPG | Much smaller | Small loss, rarely visible at 90 | Yes, if it is a photograph |
| PNG logo or screenshot to JPG | Often a little smaller | Edges and text can look smudgy | Usually no. Keep PNG |
| JPG to PNG | Larger | None. It cannot restore detail already lost | Only if a form demands PNG |
| WebP to JPG | Often larger | Small loss from JPG | Yes, to make the picture open anywhere |
| JPG to WebP | Often smaller | Small extra loss | Yes, for your own website |
These are typical results, not rules. The picture itself decides. Check the size the tool shows after converting.
Quality: where to set the slider
For JPG and WebP, the quality slider trades size against detail. At 90 a photograph looks identical to the original to most people. Around 80 the file is clearly smaller and still looks good. Below about 60 you start to see blocky patches in smooth areas such as skies, and fuzzy edges around text.
- Visible damage10–60
- Good for the web60–85
- Looks like the original85–100
A rule of thumb, not a standard. Pictures with fine detail show loss sooner than plain ones.
Transparent backgrounds
JPG has no way to store a see-through background, so a logo with a transparent area has nothing to show there when it becomes a JPG. If transparency matters, convert to PNG or WebP instead, and look carefully at the result before you use it. If the aim is to make a background transparent in the first place, see how to remove a background from a photo.
When a form still rejects the picture
- Wrong size in KB. Converting to JPG may not be enough. Use Compress Image to Exact KB next. The full routine is in how to compress an image to 50 KB or 100 KB.
- Wrong size in pixels. Resize the picture after converting. See how to resize an image to exact pixels.
- An iPhone photo. It may be HEIC rather than a normal picture. Use the HEIC to JPG Converter.
- A document, not a photo. If the form wants a single file for several pictures, combine them with the Image to PDF Converter.
Private by design
Pictures often include faces, documents and screenshots you would rather not hand to a stranger. The converter redraws the picture inside your browser and saves the new file on your device, so the original is not uploaded to a server. For what a photo can carry inside it, such as where it was taken, read your photo may be carrying your home address.
To turn PDF pages into JPG or PNG pictures, see how to convert a PDF to JPG or PNG. For photos that must meet ID rules, see how to make passport size photos at home.
Questions people ask
How do I convert PNG to JPG?
Open the Image Converter, add your PNG, choose JPG, leave the quality at 90 and press Convert. The new JPG keeps the same width and height. This works best for photographs; logos and screenshots usually look better as PNG.
How do I convert WebP to JPG?
Add the WebP file to the Image Converter, choose JPG as the format and convert. You get a JPG that opens in any program and is accepted by most upload forms.
Why can’t I just rename a .webp or .png file to .jpg?
Renaming changes only the name, not the way the picture is stored inside. Many programs read the contents rather than the name, so the file still fails. Converting re-saves the picture properly in the new format.
Is JPG or PNG better quality?
PNG keeps every pixel, so it is lossless. JPG discards a little detail to make smaller files. For photographs JPG at high quality looks the same to most eyes; for logos, text and screenshots PNG looks sharper.
Does converting to JPG reduce quality?
A little, because JPG is lossy. At the default quality of 90 the difference is rarely visible. Lower settings make smaller files with more visible loss.
Why did my file get bigger after converting?
Converting JPG to PNG makes files larger because PNG stores every pixel. Converting WebP to JPG can also make a file bigger, since WebP is more efficient.
Can I keep a transparent background when converting?
Only in formats that support transparency, which are PNG and WebP. JPG cannot store a see-through background, so choose PNG or WebP if you need to keep it.
Is it safe to convert images online?
It is safest when the work happens on your device. The Image Converter on Toolcloak processes the picture in your browser, so it is not uploaded to a server.