Convert JPG to PNG Online Free – Lossless Container, Not Lost Detail
Re-container JPG images as PNG files without uploading them. This page is explicit about what that does and does not do: the pixels are stored losslessly from now on, but the detail JPEG already discarded stays gone, and the file usually grows.
PNG is a lossless container for the pixels JPEG already produced. It does not restore detail, remove JPEG artifacts or add transparency, and the output is usually larger.
Drop JPG images here to convert to PNG
Click to browse, drag and drop, or paste from clipboard
Accepts .jpg and .jpeg files and outputs .png. Processed entirely in your browser.
Larger selections show a memory caution you can skip. Our measured laptop runs completed up to 100 MB for tools like this; phone browsers warn earlier.
Network requests reported while processing: 0
Counted during an automated browser test that processed a real file, excluding the page's own HTML, CSS, and script downloads. Saved in docs/test-results/jpg-to-png.json.
How to use JPG to PNG
- 1 Drop one or more .jpg or .jpeg files into the workspace.
- 2 The browser decodes each photo and writes a PNG immediately; there is no quality slider because PNG encoding is lossless.
- 3 Compare the original and PNG byte sizes in the result list; growth is expected.
- 4 Download files individually or as one ZIP archive.
What it does — and what it doesn't
The JPEG is decoded into a pixel bitmap, drawn onto a canvas and encoded as PNG. EXIF orientation is applied by the browser during decoding, so a portrait phone photo comes out upright; the PNG itself carries no EXIF chunk. No additional lossy step is applied, but no detail is invented either: JPEG artefacts present in the source remain in the PNG. The canvas has no alpha data from an opaque JPEG, so the PNG is fully opaque. Batch files are processed in local memory and never transmitted.
Limits and browser boundaries
- PNG cannot recover detail removed by JPEG compression or remove existing artefacts. It is a new container, not a repair.
- No transparency is added. An opaque JPEG produces an opaque PNG.
- PNG files are usually larger than the JPEGs they came from, sometimes several times larger, because lossless storage keeps every pixel.
- EXIF, GPS and ICC colour-profile metadata are dropped by the canvas round-trip.
- Images above 16,777,216 pixels are downscaled for iOS Safari; batches above 100 MB show a memory warning you can skip, and phone browsers warn earlier.
Measured on our test files
Real numbers recorded in automated browser tests, saved in docs/test-results/jpg-to-png.json.
| Fixture / Scenario | Input | Output / Result | Duration |
|---|---|---|---|
| JPG to PNG (orientation-6.jpg)orientation-6.jpg | 1.1 KB | PNG orientation-6.png 1.1 KB → 165 B (32×64 px) | — |
| JPG to PNG (quadrants-64x32.jpg)quadrants-64x32.jpg | 1.1 KB | PNG quadrants-64x32.png 1.1 KB → 176 B (64×32 px) | — |
| JPG to PNG (sample-photo.jpg)sample-photo.jpg | 192.9 KB | PNG sample-photo.png 192.9 KB → 1.4 MB (848×1264 px) | — |
Client-Side Privacy Proof
All computation executes strictly inside your device CPU and GPU memory. Your file bytes, photos, and document text are never uploaded or transmitted to any server.
Verify it yourself in 5 seconds:
- Press F12 (or right click → Inspect) and switch to the Network tab.
- Drop your file into the tool above and click process.
- Confirm that zero outbound requests or file payloads leave your computer.
Frequently asked questions
Does converting JPG to PNG improve the image quality?
No. The JPEG is already compressed, and its artefacts are part of the pixels. PNG stores those pixels exactly, so it prevents further loss from future saves but cannot restore what the camera or an earlier export discarded.
Will the PNG have a transparent background?
No. JPEG has no alpha channel, so there is no transparency to carry over. If you need a cut-out, remove the background first in an editor, then export a PNG from there.
Why did the file get bigger?
PNG is lossless. It keeps every pixel instead of approximating blocks of colour the way JPEG does. For photographic images, that usually means a much larger file; for flat graphics it can sometimes be smaller.
When is JPG to PNG useful?
When a workflow or an app requires PNG and you want to avoid another lossy JPEG save while annotating, cropping or combining images. It is a container change for editing, not a quality upgrade for delivery.
Can I batch-convert and keep the original file names?
Yes. Each output uses the original base name with a .png extension, and multiple results can be downloaded as one ZIP. Files are processed locally, with no account or quota.
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