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Compress JPG images online

Make your JPG / JPEG photos dramatically smaller without an obvious drop in quality. Drop your images below, pick a quality level, and download — all in your browser, nothing uploaded.

Drop JPG images here or browse

JPG · JPEG · PNG · WebP — or paste with Ctrl/⌘ + V

    🔒 Your JPGs are compressed entirely on your device. Nothing is uploaded.

    How to compress a JPG

    1️⃣

    Add your JPGs

    Drag and drop one or many JPG/JPEG files, paste from your clipboard, or click to browse.

    2️⃣

    Pick a quality

    80% is the sweet spot for photos. Lower it for smaller files, raise it for maximum detail.

    3️⃣

    Download

    Grab each image, or download everything as a single ZIP. You'll see the exact size saved.

    Tip: for the smallest possible files, switch the output format to WebP, or resize large photos down for the web.

    What JPEG throws away

    JPEG compression works by discarding information human vision is bad at noticing. The image is converted from RGB into a brightness channel and two colour channels, because the eye resolves brightness detail far more sharply than colour detail. The colour channels are then usually stored at half resolution — chroma subsampling — which removes three quarters of the colour data before compression has even started, and is almost invisible on photographs.

    Each 8 × 8 block of pixels is then transformed into frequency coefficients by a discrete cosine transform, and those coefficients are divided by values from a quantisation table and rounded. High-frequency detail — fine texture, sharp edges — gets rounded away first. The quality slider is essentially a multiplier on that table.

    This explains exactly what JPEG is good and bad at. Photographs are mostly smooth gradients and irregular texture, which survive the process well. Text, screenshots, logos and line art are made of hard edges, which are high-frequency by definition, so they acquire the grey halos and speckle known as ringing or mosquito noise. For those, PNG or WebP is the right format, not a higher JPEG quality.

    Choosing a quality level

    The quality number is not a percentage of anything and is not comparable between encoders — quality 80 in one library does not match quality 80 in another. What is broadly consistent is the shape of the curve: file size falls steeply between 100 and about 85 with almost no visible change, then levels off while artefacts start becoming visible below roughly 70.

    For photographs on the web, 75 to 85 is the practical sweet spot, and going from 95 to 85 typically halves the file for a difference most people cannot see side by side. Below 60, block edges become apparent in smooth areas such as skies and skin.

    Image content changes the calculus. A photograph with large flat regions shows banding and blocking sooner, while a busy, detailed scene hides artefacts and tolerates lower quality. Judge at the size the image will actually be displayed, not zoomed in — artefacts visible at 300 percent may be entirely invisible at 100.

    Generation loss is the real hazard

    JPEG is lossy every time it is encoded, not only the first time. Open a JPEG, make a small edit, save it again, and the whole image is re-quantised — including the parts you did not touch. Repeat that a dozen times and the degradation is unmistakable: colours drift, edges grow halos, and flat areas turn blotchy.

    The practical rules follow directly. Keep an original in a lossless format if the image will be edited more than once. Do all editing in one session and export once at the end rather than saving intermediate JPEGs. Never re-compress a JPEG that has already been compressed hard, since you are quantising already-quantised data and the artefacts compound.

    Lossless rotation is a special case worth knowing: rotating by exact multiples of 90 degrees can be done by rearranging the encoded blocks without decoding, and good tools do it that way. Rotating by an arbitrary angle cannot, and forces a full re-encode. If a photograph only needs straightening to upright, that operation costs nothing in quality. To move to a more efficient format entirely, WebP conversion typically saves another 25 to 35 percent at matched quality.

    Compress JPG — FAQ

    Does compressing a JPG reduce its quality?

    JPG is a lossy format, so compression trades a little fine detail for a much smaller file. At around 80% quality the difference is usually invisible. Use the slider to find the balance you like.

    How much smaller will my JPG get?

    Most photos shrink by 50–80%. Converting to WebP can save even more. The exact saving is shown for every image before you download.

    Can I compress many JPGs at once?

    Yes — drop in as many as you like and download them together as a ZIP. There's no file count limit.

    Is it free and private?

    Completely. No sign-up, no watermark, and every image is processed locally in your browser, so your photos are never uploaded.

    What quality setting should I use?

    75 to 85 for photographs on the web. The size-versus-quality curve is steep above 85 and flat below it, so dropping from 95 to 85 often halves the file with no visible difference. Below 60, blocking becomes noticeable in skies and skin.

    Does re-saving a JPEG make it worse?

    Yes. Every save re-quantises the entire image, including untouched areas. Keep a lossless original for anything you will edit more than once, and export to JPEG only at the end.