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JPG to PNG Converter

Convert a JPG to a lossless PNG in your browser. Nothing more is lost from here on, though the JPEG's existing compression stays.

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Quick answer

JPG to PNG decodes your JPEG and re-saves it as a PNG on an HTML5 canvas, in your browser. PNG is lossless, so nothing more is thrown away from this point, but the compression the JPEG already applied stays and lost detail does not come back. PNGs of photos are usually larger than the JPG. What you gain is a lossless file that is safe to edit and can hold transparency. The photo stays on your device.

  • LosslessPNG output
  • Largerusual file size
  • Samewidth and height
  • 0files uploaded

What the JPG to PNG Converter does

A JPEG is already compressed and lossy. Converting it to PNG puts those exact pixels in a lossless container. That helps when you plan to edit the image many times, when an app demands PNG, or when you want transparency, which a JPEG cannot hold.

What it will not do is improve the picture. PNG faithfully stores whatever the JPEG decoded to, artefacts and all; it cannot reconstruct detail the original compression discarded. Expect the same image, in a bigger, lossless file.

What converting can and can't do

stops extra loss on every re-savecan hold transparency laterpasses PNG-only uploadswon't remove JPEG blocks or haloswon't bring back lost detail
Use the PNG as a safe container for editing. It doesn't repair the photo.

How it works

The browser decodes your JPEG and draws it onto an HTML5 canvas at full size. JPEG has no transparency, so the canvas simply holds the opaque photo.

The canvas is exported as a PNG. PNG encoding is lossless (browsers ignore the quality value for PNG), so every pixel on the canvas is stored exactly. You download a .png with the same dimensions and base name.

Processing pipeline

  1. Step 1. Drop in a JPG (any common image works). It is decoded on your device.
  2. Step 2. A canvas is created at the image's exact width and height, and the photo is drawn onto it.
  3. Step 3. The canvas is encoded as a lossless PNG, so the quality setting is ignored.
  4. Step 4. Every pixel is stored exactly as decoded; nothing further is discarded.
  5. Step 5. The .png downloads with your original filename; dimensions are unchanged.

Privacy

Conversion runs entirely on your device. The JPG is decoded and re-encoded in the page's memory, and no server receives a copy.

The page keeps neither image. Refresh or close the tab and both are cleared, which makes it fine for private photos and scanned documents.

Technical details

EngineHTML5 Canvas (browser-native)
OutputPNG (.png), lossless
QualityLossless; PNG ignores the quality value
TransparencyPNG supports alpha; a JPEG source is opaque
File sizeUsually larger than the JPG
DimensionsUnchanged width and height
UploadNone; the JPG is converted on your device

Standards and references

  • ISO/IEC 10918 (JPEG): the lossy source format. Its compression is already baked in before conversion, and PNG cannot reverse it.
  • ISO/IEC 15948 (PNG): the lossless target: DEFLATE compression plus an optional alpha channel, storing the decoded pixels exactly.
  • HTML Canvas API: toBlob('image/png') encodes losslessly; for PNG the browser ignores any quality argument.

Accuracy and limits

The conversion loses nothing further, but it restores nothing either. PNG records exactly what the JPEG decoded to, including any blocking or halo artefacts, and cannot rebuild detail discarded when the JPEG was first saved.

Expect the file to grow, often substantially. PNG's lossless compression is far less efficient on photographic content than JPEG's lossy compression, so a photo saved as PNG is typically several times larger than the JPG.

The output is opaque. A JPEG has no transparency to carry over, so the PNG is fully opaque. You can add an alpha channel to it in an editor later.

Dimensions are preserved exactly; the tool never resizes. Very large images just use more memory during encoding.

Same picture, bigger file

JPGPNG, often several times larger
PNG's lossless compression handles photos poorly, so the file grows while the image stays the same.

Real-world uses

Prep for editing

Move a JPG into a lossless PNG so repeated edits and re-saves do not stack up more JPEG loss.

Meet a format requirement

Satisfy a tool, asset pipeline, or upload field that specifically needs PNG.

Add transparency later

Get the image into a format that supports an alpha channel so you can cut out a background in an editor.

Crisp UI assets

Store screenshots or graphics as lossless PNG when you do not want any further compression.

When it fits, and when it doesn't

Good for

  • A lossless copy for repeated editing
  • Tools that require PNG specifically
  • Getting into a format that supports transparency
  • Screenshots and flat graphics

Not the best choice for

  • Trying to improve a JPEG's quality
  • Keeping file size small (PNG grows)
  • Photos headed straight for the web
  • Recovering detail JPEG already lost

If you want a smaller file, keep the JPG or convert to WebP; PNG is the choice when you need lossless or transparency, not a size cut.

Frequently asked questions

Will converting to PNG improve my JPG's quality?
No. Conversion cannot add back detail the JPEG already discarded. PNG stores the exact decoded pixels, artefacts included, and loses nothing further, but it restores nothing.
Why is the PNG bigger than my JPG?
PNG is lossless, and lossless compression is much less efficient on photographs than JPEG's lossy compression. A photo saved as PNG is commonly several times larger than the JPG.
Is the conversion itself lossless?
Yes. PNG encoding does not discard anything, so every pixel currently on the canvas is stored exactly. The only loss already happened inside the original JPEG.
Does the PNG have transparency?
Not from a JPEG source. JPEGs are always opaque, so the PNG is opaque too, but PNG supports an alpha channel, so you can add transparency afterwards in an image editor.
Are my files uploaded?
No. The JPG is decoded and re-encoded on an HTML5 canvas in your browser. Nothing is sent anywhere, and closing the tab clears it from memory.
Do the dimensions stay the same?
Yes. The PNG keeps the JPG's exact width and height; the tool does not resize.
When should I prefer PNG over JPG?
When you need a lossless master for repeated editing, a format that supports transparency, or crisp edges on graphics and screenshots. For photos where size matters, JPG (or WebP) is usually better.
Can I convert other formats to PNG here too?
Yes. It accepts any image your browser can open and outputs a PNG. A WebP, for example, keeps its transparency in the PNG.
Is my original JPG changed?
No. A new .png is created and your JPG is left untouched.
Does it work on mobile?
Yes, in any modern mobile browser. Large images simply use more memory while encoding.

References

Written from the canvas conversion this page runs. It keeps every decoded pixel and cannot undo the JPEG's own compression.

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