How to Convert Images Between Formats Without Losing Quality
· 5 min read
Converting to PNG is lossless; converting to JPG or WebP is not. Converting a JPG to PNG does not restore what the JPG already discarded — it preserves the existing artefacts perfectly in a much larger file. Always convert once, from the highest-quality original you have, rather than chaining conversions.
Some format conversions are lossless and some are not. Knowing which is which is the whole difference between a clean conversion and a slowly degrading file.
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Which conversions actually lose something
Converting to PNG is lossless — every pixel is preserved exactly, whatever the source was. Converting to JPEG or WebP is lossy: data is discarded to make the file smaller, and it cannot be recovered.
Crucially, converting a JPEG to a PNG does not restore what the JPEG already threw away. It preserves the JPEG's artefacts perfectly, in a much larger file. The damage happened at the first encode.
| From → To | Result |
|---|---|
| PNG → PNG | Lossless |
| PNG → WebP (lossless mode) | Lossless, ~26% smaller |
| PNG → JPEG | Lossy, transparency lost |
| JPEG → PNG | No further loss, but much larger |
| JPEG → JPEG | Lossy again — avoid |
The rule that avoids nearly all of it
Always convert from the highest-quality original you have, and convert once. A chain of conversions compounds loss at every lossy step, and the result is visibly worse than a single conversion from the source.
If you find yourself converting a file you already converted, go back and find the original instead.
Convert ImageSwitch between PNG, JPG and WebPTransparency is the other thing to watch
JPEG cannot store transparency at all. Converting a PNG with a transparent background to JPEG fills that background with a solid colour, usually black or white, and there is no way back.
If your image has transparency and you want it smaller, WebP is the answer: it supports an alpha channel and still compresses far better than PNG.
Metadata and what else gets dropped
Conversion usually discards EXIF metadata: the camera model, the exposure settings, the date and often the GPS coordinates. For sharing that is frequently a feature rather than a loss, since location data in a photograph is more revealing than most people expect.
If you need the metadata kept, check before converting in bulk. Recovering it afterwards means going back to the originals.
Colour profiles
Images from a camera or a design tool often carry a colour profile describing how their colours should be interpreted. Dropping it can shift colours noticeably, usually making them look flat or oversaturated.
For anything colour-critical, convert once from the original and compare the result side by side rather than trusting that it came through.
Generation loss, and why it sneaks up on people
Each lossy save discards detail based on what is in the image at that moment — including the artefacts introduced by the previous save. So the second encode compresses the first encode's mistakes, and treats them as real detail worth preserving.
The effect is invisible for one or two rounds and unmistakable by the fifth. It is why an image that has been through a few chat apps, a screenshot, and a re-upload looks the way it does, and why nothing can restore it.
The practical defence is a workflow rule rather than a setting: keep one lossless master, and treat every exported JPEG or WebP as disposable output you can regenerate.
Deciding in one line
Nearly every real conversion question resolves to what the image is for and what it must keep. This is the whole decision in one table.
| What you need | Convert to | Watch out for |
|---|---|---|
| Smallest file for the web | WebP, lossy 80 | Old email clients cannot render it |
| Transparency preserved | WebP or PNG | JPEG fills it with solid colour |
| Editable master copy | PNG | Large files, no camera metadata |
| Maximum compatibility | JPEG | No transparency, lossy every save |
Common questions
Which image conversions are lossless?
Anything into PNG, and PNG into WebP's lossless mode. Both preserve the pixels they are given exactly. Note the distinction: JPEG to PNG adds no new loss, but it does not undo the loss already baked into the JPEG.
Does converting JPEG to WebP lose quality?
Converting JPEG to WebP in lossy mode (the default for photos) applies additional compression, but at 80%+ quality the difference is visually imperceptible. The resulting WebP will typically be 25–34% smaller than the JPEG.
Why does PNG to JPEG always lose quality?
JPEG uses lossy compression and doesn't support transparency. When you convert a PNG to JPEG, the algorithm discards colour data it considers imperceptible. Repeated save cycles degrade quality further — this is called 'generation loss'.
What is the best format to convert everything to?
WebP is the modern answer for web images. It supports both lossless and lossy compression, has full transparency support, is 25–34% smaller than JPEG, and works in all modern browsers.
Can I convert between formats without Photoshop?
Yes. FileCrisp converts between PNG, JPEG, and WebP entirely in your browser — no Photoshop, no Lightroom, no install required. Free, private, and instant.
Does converting an image remove its EXIF data?
Usually yes — camera model, exposure settings, timestamps and GPS coordinates are dropped. For sharing that is often desirable, since location data in a photo reveals more than most people intend. If you need it kept, check before converting in bulk.
How many times can I re-save a JPEG before it looks bad?
There is no fixed number, but the damage compounds because each save compresses the previous save's artefacts as though they were real detail. One or two rounds are invisible; by around five it shows. Work from a lossless master instead.
Is converting the same as compressing?
No, though they often happen together. Converting changes the container and the encoding scheme; compressing changes how much detail is discarded within one. You can convert without compressing further, and compress without changing format.