Compress JPEG Images Free — You Choose How Much Quality to Spend
Make a JPG smaller without sending it anywhere. Pick a quality level, compress as many files as you like, and if nothing we produce beats your original, you get your original back rather than a bigger file.
Quick answer: To compress a JPEG free, drop it into the Convertlo image compressor, leave quality around 75–80, and download the result. It stays a JPEG, it runs entirely in your browser, and the output is never larger than the file you started with.
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JPEG does not store your pixels. It stores a mathematical approximation of them, and the quality setting decides how rough that approximation is allowed to be. At quality 90 the encoder keeps detail almost nobody can see, which is why the file stays large. Drop to 80 and it discards the highest-frequency detail first — the part your eye is worst at noticing — and the file falls off a cliff. That is why the interesting range is narrow.
Convertlo caps quality at 82 deliberately. Above that you pay in file size for detail that will not survive being viewed on a screen, and the encoder is still lossy, so you get the worst of both. Below about 70, blocking starts to show on smooth gradients like skies and skin.
Where JPEG is the wrong answer
JPEG was designed for photographs — continuous tone, no hard edges. Give it a screenshot, a logo, a chart or anything with text and the artifacts appear immediately as a halo around every edge, because sharp transitions are exactly the high-frequency detail JPEG throws away first.
For those images, compressing as PNG keeps every pixel exactly, and our PNG compressor re-encodes losslessly rather than degrading anything. If the file still needs to be smaller after that, WebP handles both photographs and flat graphics better than JPEG does at the same size.
Compressing the same file twice
Generation loss is real and it is not recoverable. Every JPEG save re-quantises the image, so a file compressed three times has been approximated three times, each pass working from the previous pass's damage rather than from your original. The artifacts compound in a way that no later step can undo.
Work from the original every time. If you need several sizes or several quality levels, export each one from the source file rather than from an earlier export.
Frequently Asked Questions
No, and it cannot be. JPEG is a lossy format by design, so every save discards some detail. What a good compressor controls is how much. Convertlo caps quality at 82 because above that the file barely shrinks while the encode still throws away data, and it will not hand back a file larger than the one you gave it.
Around 75 to 82 for photographs, which is where the file drops sharply while the picture still looks untouched at normal viewing size. Go lower only for thumbnails or images that will be displayed small. Flat graphics, screenshots and anything with text or hard edges show JPEG artifacts early, so those belong in PNG or WebP rather than a lower JPEG quality.
It was probably already compressed. A photo exported by a phone or by Lightroom has usually been through a good encoder once, so a second pass finds little left to remove and mostly adds artifacts. When nothing we produce beats the original, you get the original file back untouched and the result says no change.
Yes. Each JPEG save re-quantises the image, and the damage accumulates — this is generation loss. Always compress from the original file rather than from an already-compressed copy, and keep the original if you might need to re-export later.
No. The compression runs in your browser, so the file never leaves your device. That holds for every image, at any size, and there is no queue and no account.
No account limits. You can compress many images in one go, and because the work happens on your own machine rather than a shared server, large files are limited only by your device's memory.