Image Converter — PNG, JPEG & WebP
Convert and compress images entirely in your browser. The file is decoded and re-encoded on your device and is never uploaded.
Image Format Converter
Convert images between JPEG, PNG, WebP, and BMP — entirely in your browser, no upload needed.
Choosing a format
| Format | Compression | Transparency | Best for |
|---|---|---|---|
| PNG | Lossless | Yes, full alpha | Screenshots, diagrams, logos, anything with text or hard edges |
| JPEG | Lossy | No | Photographs. Universally supported, still the safest choice for email and older software |
| WebP | Both, selectable | Yes, full alpha | The web default — typically 25–35% smaller than JPEG at equivalent quality |
AVIF compresses better still, but browser encoding support is inconsistent, so it is not offered here. Encode AVIF in your build pipeline and serve it with a WebP or JPEG fallback.
Generational loss, and why re-saving degrades images
Lossy formats discard information permanently. JPEG works by transforming 8×8 blocks of pixels into frequency components and throwing away the ones the eye is least sensitive to. That discarded data is gone — decoding produces an approximation of the original, not the original.
The consequence is generational loss. Each save-decode-resave cycle discards a little more, and the damage compounds: blocking artifacts around edges, colour banding in smooth gradients, and a halo effect known as ringing around high-contrast boundaries. This is the mechanism behind the familiar look of an image that has been screenshotted and reposted many times.
Two practical rules follow. Always convert from the highest-quality original you have rather than from an already-compressed copy — converting a quality-60 JPEG to WebP at quality 90 produces a larger file that still contains every one of the original's artifacts. And never use a lossy format as a working file; keep the source as PNG or the editor's native format and export to lossy only at the end.
Converting to a lossless format does not repair anything. PNG will faithfully preserve the JPEG artifacts already present, at a much larger file size.
Picking a quality setting
For JPEG and lossy WebP, quality is a trade-off curve with a clear knee:
- 90–100 —Visually indistinguishable from the original, but file size rises steeply for almost no perceptible gain. Worth it only for images that will be edited further.
- 75–85 —The sweet spot for web delivery. Artifacts are essentially invisible at normal viewing size while files are dramatically smaller. Start at 80.
- 60–75 —Acceptable for thumbnails and background imagery where fine detail does not matter.
- Below 60 —Visible degradation on most photographs — blocking in flat areas and mush around edges. Reserve for placeholders and low-quality image previews.
- Text and line art —Do not use a lossy format at all. JPEG artifacts cluster around exactly the high-contrast edges that text is made of, and even quality 95 looks smeared. Use PNG or lossless WebP.
About
The Image Format Converter converts images between JPEG, PNG, WebP, and BMP formats entirely in your browser using the HTML5 Canvas API — your image never leaves your device. Drop or select any image file, choose the output format, adjust the quality for lossy formats (JPEG and WebP), and click Download to save the converted image. JPEG conversion automatically fills transparent areas with white, since JPEG does not support transparency. PNG and WebP preserve transparency. The converter works with any image your browser can decode, including JPEG, PNG, WebP, GIF, AVIF, SVG, and BMP.
How to use
- 1 Drag and drop an image file onto the drop zone, or click to browse and select a file.
- 2 The image preview and file info (dimensions, size, format) appear immediately.
- 3 Select the output format: JPEG, PNG, WebP, or BMP.
- 4 For JPEG or WebP, adjust the Quality slider (higher = larger file, better quality).
- 5 Click Download to convert and save the image to your device.
- Which format should I use — JPEG, PNG, or WebP?
- Use JPEG for photographs and complex images where small file size matters and transparency is not needed. Use PNG for images with transparency, screenshots, logos, or images with text where lossless quality is important. Use WebP for web images where you want the best of both worlds — WebP supports both lossy and lossless compression and typically achieves 25–34% smaller files than JPEG/PNG at equivalent quality. WebP is supported in all modern browsers.
- Does my image get uploaded to a server?
- No — everything happens locally in your browser. The image is read using the File API, processed using the HTML5 Canvas API, and downloaded directly to your device. No data is sent to any server.
- Why does converting PNG to JPEG remove transparency?
- JPEG does not support an alpha (transparency) channel. When converting a PNG with transparency to JPEG, this tool fills transparent areas with white. If you need to preserve transparency, use PNG or WebP as your output format instead.
- What quality setting should I use for JPEG?
- A quality of 85–92 is a good balance between file size and visual quality for most photographs. Values above 95 produce only minor quality improvements with significantly larger files. Values below 70 can produce visible compression artifacts. For web use, 80–90 is typical; for archival purposes, 95+ is recommended.
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