Resize a JPG Image
A JPEG cannot be resized without being rebuilt. The file is decoded to raw pixels, resampled to the dimensions you asked for, then handed to your browser's JPEG encoder for a fresh compression pass — all of it on your own machine, with nothing sent anywhere. That final encode is where the quality of the result gets decided, so the sections below explain what it costs, what the slider controls, and which parts of the original file survive.
One resize, one generation of loss
JPEG compression throws information away every time a file is written, so a resized JPEG carries whatever its first save discarded plus the cost of the new encode. The slider in the panel controls that second pass and sits at 90 unless you move it — a setting chosen so the fresh generation of loss stays invisible on photographs viewed at ordinary size.
Direction matters more than the slider does. Shrinking a photo averages clusters of pixels into one, and that averaging scrubs out much of the blockiness and ringing the original was carrying, which is why a 4000-pixel image brought down to 1200 tends to look cleaner at that size than its source did. Enlarging works against you twice: the resampler has to invent pixels it cannot know, and the encoder then spends bytes compressing the invention. Tick "Do not enlarge if smaller" and the tool refuses to do it.
Colour is stored at a quarter of the detail
JPEG encoders, the browser's included, typically keep the brightness channel at full resolution while storing the two colour channels at a quarter of the pixel count — a trick called chroma subsampling that human eyes barely register on natural images. It is the main reason JPEG files are as small as they are.
It is also the reason certain images fall apart in this format. Saturated red lettering, thin coloured chart lines and syntax-highlighted code all live in exactly the detail the colour channels no longer have, so their edges smear. Resizing re-applies the subsampling to the new pixel grid, and hairline colour details that barely survived the first save can visibly degrade at the new size. If your image is that kind of graphic, it belongs in PNG rather than in a smaller JPEG.
Orientation survives; the metadata does not
Cameras and phones often store the image sideways and record the intended rotation as a flag in the header. The decoder applies that flag before any resampling happens here, so your output stands upright with the rotation baked permanently into the pixels — no app needed to interpret it ever again.
Everything else in the header is gone, because the output is rebuilt from bare pixels: camera model, exposure settings, the GPS coordinates of where the shot was taken, the embedded colour profile, and the progressive scan structure if the original had one — the browser writes a plain baseline file. For a photo headed to a stranger, losing the location data is usually a feature. For an archive, keep the original alongside the resized copy.
Frequently Asked Questions
What quality setting should I use for the re-encode?
Leave it at 90 unless you have a reason to move it. Sliding below about 80 starts to show on smooth gradients such as skies and skin, while pushing to 100 grows the file substantially for a difference you will struggle to find. The slider only matters for lossy output; it changes nothing on a PNG.
Why did my JPG come out larger even though I made it smaller?
Because the encode is new. If the original was saved at a harsher setting than 90, re-encoding fewer pixels at a gentler quality can still cost more bytes. Lower the slider, or hand the result to the compressor, which targets file size directly.
Does resizing remove the GPS location from a photo?
Yes. The whole EXIF block is dropped, coordinates included, because the output file is rebuilt from pixel data alone. Nothing from the header survives except the rotation, which is applied to the image itself rather than copied over.
My phone photo always arrives sideways. Will the resized one?
No. The orientation flag is honoured during decode, so the output is upright everywhere — including in software that ignores such flags, since the pixels themselves are rotated.
Can I do a stack of JPEGs in one go?
Yes — the dropzone accepts up to ten files within 50 MB, all resized with the same settings. The bulk resize page covers that workflow, including what fixed dimensions do to a mix of portrait and landscape shots.
Can I get a WebP or PNG out instead of a JPEG?
Not here — a JPG in means a JPG out, since this tool has no format switch. Resize first, then run the download through the image converter to change formats without another resample.