OneTaskBy Tim King · Updated
PNG to JPG and JPG to PNG Converter
Convert PNG to JPEG and JPG Back to PNG, With a Quality Slider
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How the PNG To JPG works
This PNG to JPG converter flattens transparency onto a colour. Drop a PNG on the page and it is re-encoded as a JPG at the quality you choose, with an optional maximum width. The before-and-after sizes are shown at once, so you can nudge the slider until the file is small enough and the preview still looks right, then download. Drop a JPG instead and the same page converts it to a lossless PNG: the output is always the format you did not drop.
PNG to JPG: what to know first
PNG to JPG is the conversion people reach for when a file is too big: a screenshot that will not fit an upload limit, a photo exported from an editor as PNG by default, a batch of product shots that need to load quickly.
Why the JPG is so much smaller. PNG stores every pixel exactly. JPEG discards fine detail the eye is least sensitive to, and for photographic content that removes most of the data with little visible change. A 4 MB PNG photo typically becomes a 300 to 600 kB JPG at quality 85. For screenshots and graphics the saving can be small or none at all, and the JPG is sometimes bigger than the PNG. Those images also suffer most from JPEG's artefacts, so for flat colour and text keep the PNG or try a lossless WebP. The size change shown after conversion tells you which case you are in.
Transparency is lost. JPEG has no alpha channel. Any transparent or semi-transparent pixels in the PNG are composited onto a white background before encoding, which is the conventional choice and looks right on most pages and documents. If the image will sit on a dark background, convert to WebP instead, which keeps the transparency.
Choosing a quality. The slider is not a percentage of anything; it controls how aggressively the encoder rounds off detail, and the response is steep at both ends. 100 to 90 roughly halves the file with no visible change; 90 to 80 saves a little more and is still hard to spot; below 60 the blockiness in smooth areas becomes obvious. 85 is the default here because it is where most people stop noticing a difference.
Width. Leave blank to keep the original size. A cap scales the image down proportionally before encoding. For anything destined for a web page or a message this saves more than the quality slider does, because file size follows pixel count far more closely than it follows quality.
Going the other way: JPG to PNG
JPG and PNG are the two formats every piece of software understands, and converting between them is usually about what happens next to the picture rather than how it looks now.
Why convert a JPG to PNG at all. A JPEG loses a little more detail every time it is saved, because the encoder re-quantises the image on each pass. If you are about to edit a photo through several rounds — cropping, adjusting, adding text — converting to PNG first means only the original JPEG compression is baked in and nothing else stacks on top. PNG is also what many upload forms, document tools and print workflows insist on, and it is the format to use when a picture needs a transparent region added later, since JPG cannot hold one.
What it will not do. Converting does not recover any detail the JPEG already threw away. The PNG is a faithful copy of the decoded JPEG, blocks and ringing included, so a heavily compressed JPG stays a heavily compressed-looking image; it simply stops getting worse. The file will also be larger — often three to ten times larger for a photograph — because PNG's lossless compression has very little to work with in the smooth gradients and noise of a photo.
The width control. Leave it blank to keep the original dimensions. Set a number and images wider than that are scaled down proportionally with high-quality resampling before encoding. Since PNG size scales with pixel count, this is the only lever that meaningfully reduces the output; a 4000 px photo capped at 1600 px is a quarter of the data.
Metadata. The JPEG is decoded to pixels and re-encoded, so EXIF data, GPS coordinates and the embedded colour profile are not carried across. If you need them preserved, keep the JPG; if you want them gone, this does it as a side effect.
FAQ
Why does my PNG to JPG conversion have a white background?
Because JPG cannot store transparency, the transparent parts have to become some colour and white is the standard choice. Use PNG to WebP if you need the transparency kept.
What quality should I use for PNG to JPG?
85 for photographs is a good default. Go to 92 or above for images with text or sharp edges, and down to 70 if the file size matters more than fine detail.
Is converting PNG to JPG lossy?
Yes. Detail is discarded and cannot be recovered from the JPG. Keep the PNG as your master copy if you may need to edit again.
Can I convert a screenshot to JPG?
You can, but text edges will show faint halos at anything below quality 90 and the saving over PNG is small. WebP is the better format for screenshots.
Does converting JPG to PNG improve quality?
No. It stops quality from getting any worse on subsequent saves, but the detail lost when the JPEG was made is gone. The PNG is pixel-identical to what the JPEG decodes to.
See also: all Images tools, Units, Audio & Video, Documents, Data & Code.