🖼️ Image Format Converter (PNG, JPG, WEBP)
By ToolNimba Editorial Team · Updated 2026-06-19
PNG, JPG, WEBP, GIF or BMP. Files stay on your device.
Applies to JPEG and WEBP only.
Choose an image to get started.
This image format converter changes a picture from one format to another (PNG, JPEG or WEBP) without installing anything. Choose a file, pick the format you want, set the quality for JPEG or WEBP, and download the result. The whole conversion happens inside your browser using the HTML canvas, so your image is never uploaded to a server. That makes it fast and completely private.
What is the Image Format Converter?
Image formats are different ways of storing the same picture, and each one makes a different trade-off between file size, quality and features. PNG is lossless and supports transparency, so it is ideal for logos, icons, screenshots and graphics with sharp edges or flat colour. JPEG (the file you usually see as .jpg) uses lossy compression that throws away detail the eye barely notices, which makes it small and perfect for photographs, but it cannot store transparency. WEBP is a newer format that often beats both: it does lossy and lossless compression and supports transparency, typically producing smaller files than JPEG or PNG at similar quality.
This tool converts by decoding your image, drawing it onto an off-screen canvas at its full resolution, and re-encoding it in the target format with the browser's built-in encoder (the canvas.toBlob method). Because it is a true re-encode rather than a rename, the output is a genuine file of the new type. For JPEG and WEBP you can set a quality value from 10 to 100 percent: lower quality means a smaller file with more visible compression, higher quality means a larger, cleaner file. PNG ignores the quality slider because it is always lossless.
The one thing to watch is transparency. PNG and WEBP can keep transparent areas, but JPEG cannot, it has no alpha channel. When you convert a transparent PNG to JPEG, those see-through areas must be filled with a solid colour, so this tool lets you choose a background fill (white by default). Converting between lossy formats, or from a lossy format back to PNG, will not recover detail that an earlier JPEG step already discarded, so always keep your original file if you can.
When to use it
- Converting a transparent PNG logo to JPEG for an email or document that does not handle PNG well.
- Turning bulky PNG screenshots or JPEG photos into smaller WEBP files to speed up a website.
- Changing a WEBP image you downloaded into JPG or PNG so an older app or printer will accept it.
- Shrinking a photo for upload by re-saving it as JPEG at a lower quality setting.
- Standardising a folder of mixed-format images to a single format one at a time, privately and offline.
How to use the Image Format Converter
- Click "Choose an image" and select a PNG, JPG, WEBP, GIF or BMP file from your device.
- Pick the format you want to convert to: PNG, JPEG or WEBP.
- For JPEG or WEBP, drag the quality slider to balance file size against image quality.
- If you are converting to JPEG, pick a background fill colour for any transparent areas.
- Click "Convert image" to see a preview, then click "Download" to save the new file.
Formula & method
Worked examples
You have a transparent PNG logo and need a JPEG for a Word document.
- Choose the PNG file. The tool reports its dimensions, for example 800x600px.
- Select JPEG as the target format. A note warns that transparency will be lost.
- Pick white as the background fill so the transparent corners become white.
- Set quality to about 90% for a clean result.
- Click Convert, then Download. You get logo.jpg with white where the transparency was.
Result: A solid-background JPEG at 800x600px, smaller than the PNG, ready to drop into a document.
You want a large JPEG photo to load faster on your website as WEBP.
- Choose the JPEG photo (say 2.4 MB at 3000x2000px).
- Select WEBP as the target format.
- Set quality to 80%, a common web sweet spot.
- Click Convert. The tool re-encodes the canvas as WEBP and shows the new size.
- Download the .webp file, often well under half the original size at similar visual quality.
Result: A WEBP file roughly 40 to 70 percent smaller than the JPEG, with no visible loss at 80% quality.
Which format to choose
| Format | Compression | Transparency | Best for |
|---|---|---|---|
| PNG | Lossless | Yes | Logos, icons, screenshots, line art, anything with sharp edges |
| JPEG | Lossy | No | Photographs and complex images where small size matters |
| WEBP | Lossy or lossless | Yes | Web images: usually smaller than JPEG or PNG at similar quality |
Rough guide to JPEG / WEBP quality settings
| Quality | Typical use | Trade-off |
|---|---|---|
| 90 to 100% | Archival, print, hero images | Largest file, no visible loss |
| 75 to 89% | General web and sharing | Good balance of size and quality |
| 50 to 74% | Thumbnails, fast-loading pages | Smaller file, some softening |
| Below 50% | Maximum compression | Smallest file, visible artefacts |
Common mistakes to avoid
- Converting a transparent PNG to JPEG and getting a black or odd background. JPEG cannot store transparency, so transparent pixels must be filled with a solid colour. If you do not set a fill, transparent areas can turn black. Choose a background colour (usually white) that matches where the image will sit.
- Expecting PNG to make a small file from a photo. PNG is lossless, so a detailed photograph saved as PNG is often much larger than the same photo as JPEG or WEBP. For photos, JPEG or WEBP almost always gives a far smaller file.
- Converting JPEG to PNG to "improve" quality. Re-saving a JPEG as PNG cannot recover detail the JPEG already discarded. You only get a bigger file containing the same compressed-looking image. Keep the original whenever you need the best quality.
- Re-compressing the same image many times. Each lossy save (JPEG or lossy WEBP) throws away a little more detail. Converting back and forth between lossy formats degrades the image step by step, so always start from your highest-quality original.
Glossary
- Lossless
- Compression that keeps every pixel exactly, so no quality is lost (PNG, and lossless WEBP).
- Lossy
- Compression that discards some detail to shrink the file, used by JPEG and lossy WEBP.
- Transparency (alpha)
- See-through areas of an image, supported by PNG and WEBP but not by JPEG.
- Quality
- A setting for lossy formats from 0 to 100 that trades file size against visible detail.
- Canvas
- A browser drawing surface used here to redraw the image and re-encode it in the new format.
- WEBP
- A modern image format that supports both lossy and lossless compression plus transparency, often smaller than JPEG or PNG.
Frequently asked questions
How do I convert a PNG to a JPG?
Choose your PNG file, select JPEG as the target format, pick a background fill colour for any transparent areas, set the quality, then click Convert and Download. The conversion happens in your browser, so the file is never uploaded.
Are my images uploaded to a server?
No. The whole conversion runs locally in your browser using the HTML canvas. Your image never leaves your device, which keeps it private and makes the conversion fast even for large files.
Why does my image lose its transparent background when I convert to JPEG?
JPEG has no alpha channel, so it cannot store transparency. Transparent areas are filled with the background colour you choose (white by default). To keep transparency, convert to PNG or WEBP instead.
Which format gives the smallest file?
For photographs, WEBP is usually smallest, often beating JPEG at the same quality, with JPEG close behind. PNG is lossless and tends to be largest for photos but is best for graphics with flat colour or sharp edges.
Does converting to PNG improve the quality of a JPEG?
No. Converting a JPEG to PNG cannot bring back detail the JPEG already removed. You simply get a larger, lossless copy of the already-compressed image. Start from the original for the best quality.
What does the quality slider do?
It controls lossy compression for JPEG and WEBP, from 10 to 100 percent. Higher values keep more detail but make a bigger file; lower values shrink the file but can introduce blurring or blocky artefacts. PNG ignores it because it is always lossless.