CONVERT
JPEG → PNG
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Fast, secure JPEG to PNG conversion. No registration required.
JPEG uses DCT-based lossy compression that permanently discards high-frequency detail by quantizing 8×8 pixel blocks — every time you save a JPEG, that information is gone for good. Converting a JPEG to PNG does not recover what was already lost, but it stops the bleeding: PNG uses DEFLATE lossless compression, so the pixel data you have now is preserved exactly through every subsequent save, edit, or export cycle. The practical reason users make this conversion is editorial continuity — they received a JPEG from a camera or the web, need to composite it into a design, annotate it, or pass it through multiple editing steps, and they cannot afford the additional generation loss that re-saving as JPEG at each step would introduce. A JPEG re-saved at quality 80 loses roughly 10–20% more fidelity per cycle; the same image saved as PNG and edited repeatedly loses nothing. The conversion also matters when the image needs to be layered over a colored or transparent background in a web or print workflow, since PNG supports an alpha channel and JPEG does not.
JPEG Image
Source formatJPEG alternate extension. Functionally identical to JPG but uses the four-letter extension. Some older systems and cameras produce files with this extension.
PNG Image
Target formatPNG is a lossless image format that supports transparency. It is ideal for graphics, logos, screenshots, and any image where preserving exact pixel data is important.
Why convert JPEG to PNG
The dominant real-world trigger is needing to edit the image more than once without accumulating compression artifacts. JPEG's block-based quantization produces ringing around hard edges and color banding in gradients — subtle in generation one, visible by generation three. Designers converting product photos for UI mockups, developers preparing sprites for web apps, and photographers exporting intermediate files for compositing all share the same need: a container that will not introduce new distortions when the file is touched again. A secondary trigger is transparency: if the JPEG needs a cutout or a soft-edge mask, only PNG can carry that alpha channel natively without adding a separate mask file.
HOW TO CONVERT
JPEG → PNG
Provide the JPEG
Click or drag to upload. We accept a single JPEG file per job, with an optional queue of additional images for batch mode.
Encode to PNG
The conversion decodes the JPEG, resolves the colour space to sRGB and writes the PNG container around the pixel data.
Save the PNG
The download is streamed back over HTTPS. If you uploaded multiple files, a ZIP with all PNG outputs is produced instead.
Common Use Cases
Share across platforms
Send PNG files to anyone without worrying about whether they have the right software for JPEG.
Embed in documents
Drop PNG output into Word, Google Docs, PowerPoint, Notion or a website without conversion warnings.
Optimize size
PNG often produces smaller files than JPEG for web, email and storage.
Archive & future-proof
Store in a widely-supported format that will still open on future operating systems without legacy plugins.
JPEG vs PNG — Strengths and limitations
What each format does best, and where it falls short.
JPEG Strengths
- Universally supported — every camera, browser, OS, and editor reads JPEG.
- Mature, deterministic, and fast to encode/decode.
- Small file sizes for photographs — DCT compression shines on continuous-tone imagery.
- Rich metadata ecosystem (EXIF for shooting data, XMP for editing, IPTC for captions).
- Progressive variant enables perceived faster loading on slow networks.
Limitations
- Lossy by design — every save further degrades quality ("generation loss").
- No transparency channel. Logos and UI elements belong in PNG or WebP.
- Terrible on flat colors, text, and sharp edges — blocking artifacts are visible.
PNG Strengths
- Lossless compression — every save preserves the original pixels perfectly.
- Full 8-bit alpha channel for smooth transparency.
- Excellent for text, UI screenshots, logos, and line art.
- Royalty-free and an ISO standard (ISO/IEC 15948).
- Supports 16-bit color depth for high-fidelity work.
Limitations
- Much larger than JPEG for photographs (no perceptual compression).
- No native animation in most software (APNG support is inconsistent).
- No CMYK support — web and screen only, not print.
JPEG vs PNG — Technical specifications
Side-by-side comparison of the technical details.
JPEG
- MIME type
- image/jpeg
- File extensions
- .jpg, .jpeg, .jpe, .jfif
- Standard
- ITU-T T.81 / ISO/IEC 10918-1:1994
- Compression
- Lossy DCT (baseline); lossless mode exists but rarely used
- Color depth
- 8-bit per channel (24-bit RGB total)
- Max dimensions
- 65 535 × 65 535 px
PNG
- MIME type
- image/png
- Standard
- ISO/IEC 15948:2004
- Compression
- Lossless — DEFLATE (zlib)
- Color depth
- 1, 2, 4, 8 or 16 bits per channel
- Max dimensions
- 2^31 − 1 pixels per side (2.1 billion)
- Transparency
- Full 8-bit alpha channel
| Specification | JPEG | PNG |
|---|---|---|
| MIME type | image/jpeg | image/png |
| File extensions | .jpg, .jpeg, .jpe, .jfif | — |
| Standard | ITU-T T.81 / ISO/IEC 10918-1:1994 | ISO/IEC 15948:2004 |
| Compression | Lossy DCT (baseline); lossless mode exists but rarely used | Lossless — DEFLATE (zlib) |
| Color depth | 8-bit per channel (24-bit RGB total) | 1, 2, 4, 8 or 16 bits per channel |
| Max dimensions | 65 535 × 65 535 px | 2^31 − 1 pixels per side (2.1 billion) |
| Transparency | — | Full 8-bit alpha channel |
JPEG vs PNG — Typical file sizes
Approximate file sizes for common scenarios.
JPEG
- Thumbnail (400px) 20-60 KB
- Web photo (1920px) 200-500 KB
- Print-quality photo (3000px) 1-4 MB
- DSLR JPEG (24 MP, quality 95) 6-12 MB
PNG
- Icon or small logo 2–20 KB
- UI screenshot (1920×1080) 200–800 KB
- High-res photo (12 MP) 10–30 MB
- Print-ready illustration 5–50 MB
Quality & Compatibility
The pixel values in the resulting PNG are a perfect copy of what the JPEG decoder produced — every RGB triplet is preserved losslessly from that point forward. However, the JPEG's original compression already degraded the image: 8×8 DCT blocks introduced mosquito noise around edges and shifted chroma values, and those artifacts are now frozen into the PNG. Bit depth stays at 8 bits per channel (24-bit RGB) unless the source JPEG carried a CMYK or grayscale color space, in which case the decoder output determines the channel count. JPEG does not have an alpha channel, so the PNG is produced without transparency unless you manually define a matte later. EXIF and ICC profile metadata can be carried over if the converter reads the JPEG APP1 and APP2 segments and writes them into PNG text or iCCP chunks; Kaijuconverter preserves ICC profiles. File size will increase — a typical photographic JPEG at quality 80 that is 400 KB will expand to 1.5–3 MB as PNG because DEFLATE cannot compress photographic noise as efficiently as DCT can.
Tips for Best Results
- If your goal is clean compositing rather than archive quality, apply noise reduction to the JPEG before converting — DEFLATE will then compress the resulting PNG more efficiently and the artifacts frozen into the file will be less visible.
- For web use after the PNG editing workflow is finished, re-export a fresh JPEG or WebP at that final step only; keeping PNG as the working master and JPEG as the delivery format gives you the best of both compression models.
- Check the color profile after conversion: if the JPEG carried an sRGB ICC profile and your editing tool interprets the untagged PNG as Display P3, colors will shift. Confirm the iCCP chunk is present in the output PNG using a tool like ExifTool before continuing work.
Frequently Asked Questions
It depends on the codecs involved. If both JPEG and PNG are lossy, the pixels are re-encoded and a small amount of detail is discarded — invisible at default quality settings on photographs. If PNG is lossless (PNG, TIFF, BMP) the output keeps every pixel of the decoded JPEG exactly, but cannot recover detail that JPEG had already compressed away.
Often yes, especially when PNG is lossless. JPEG tuned for efficient web delivery will usually produce smaller files than PNG's default settings. If file size matters, drop the quality in Advanced or pick a more compressed target format instead.
KaijuConverter uploads over HTTPS, processes the image in an isolated container and deletes both the source and the output within two hours. No account is required, file contents are never logged, and we do not use uploads to train any model. For confidential material, the paid plan includes a data-processing agreement.
Related comparisons
See these formats side by side to understand which fits your use case best.
Related Guides
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Deep dive into JPEG compression algorithms, baseline vs progressive encoding, chroma subsampling (4:4:4 vs 4:2:0), quality factors, EXIF metadata, and optimization techniques.
Read guideSecure & Private Conversion
Your files are encrypted during transfer, processed in isolated containers, and automatically deleted within 60 minutes. We never read, share, or store your data.