Resize an image
Scale to a box, a percentage, exact dimensions, or straight to a file-size limit. Works on a whole folder at once, keeps the proportions, and runs entirely on your own device.
Above 100% the image is enlarged, which cannot add detail that was never captured.
Images smaller than the target are left at their own size rather than enlarged.
Four ways to say how big
Fit inside a box is the one to reach for by default. You give the longest side you will accept and every image is scaled down to fit it, keeping its shape. Portrait and landscape photos in the same batch both come out with their long edge at your number, which is exactly what you want for a gallery, an email attachment or a set of images for a website. Images already smaller than the box are left alone rather than enlarged.
By percentage is for when you know the relationship rather than the number — halving a set of screenshots, say. Exact width and height is for a slot with a fixed shape; leave the shape lock ticked and the image is fitted inside those numbers without distortion, or untick it to stretch to exactly that rectangle. To a file size ignores dimensions and works backwards from a byte limit, which is the mode to use when a form has told you the maximum and does not care about pixels.
Hitting a file size is not the same as hitting a width
These two requirements pull in opposite directions and it is worth understanding why. A JPEG's size depends far more on how much detail is in the picture than on how many pixels it has: a photograph of foliage and a photograph of a blank wall at identical dimensions can differ tenfold. So “make this 200 KB” has no single pixel size that answers it.
The file-size mode does a binary search on the encoder's quality setting, trying about nine values to find the highest quality that still fits. If even the lowest usable quality overshoots, it steps the resolution down by a fifth and searches again, repeating until it fits. The result is the largest, sharpest image that fits your limit, rather than an arbitrary guess. That is also why it is the mode where the quality slider disappears — the search is choosing the quality, and letting you also set it would make one of the two instructions a lie.
PNG cannot do this. It is lossless, so there is no quality dial to turn; the only lever is resolution, and hitting a precise byte target that way is crude. Choosing a byte target with PNG output will give you a JPEG instead, which is nearly always what someone asking for “under 100 KB” actually needs.
DPI has nothing to do with this
If someone has asked you for a “300 DPI image”, they have probably asked you for the wrong thing, and this trips up more people than any other part of resizing. Dots per inch is not a property of the pixels in a file. It is a number written in the file's metadata that says how large to print those pixels, and changing it does not add or remove a single pixel. A 1200×1800 image is a 1200×1800 image whether its metadata says 72 DPI or 300.
What actually matters for print is pixels divided by the physical size you want. A 4×6 inch print at 300 DPI needs 1200×1800 pixels; if your file has that many, it will print fine no matter what the DPI tag says, and the printer's software will set the tag for you. If it has 600×900, no amount of changing metadata will rescue it.
This tool works in pixels only and does not write a DPI tag, because writing one would encourage exactly the confusion above. If a printer insists on a specific tag, set it in whatever they are opening the file with — it is a one-field change that alters no image data.
Enlarging does not add detail
You can scale above 100%, and sometimes you have to, but understand what happens. Enlargement invents pixels by interpolating between the ones that exist. The browser's resampler does this smoothly, so the result looks soft rather than blocky, but no information is created: a face that was twelve pixels across is not going to become recognisable. Anything advertised as AI upscaling is not recovering detail either — it is generating plausible detail, which is a different and occasionally dangerous thing if the image is evidence of something.
Shrinking is the opposite and is genuinely free: averaging many pixels into one both reduces the file and hides sensor noise and compression artefacts, which is why a downscaled photo often looks cleaner than the original at the same viewing size.
Formats, transparency and a second generation
Leave the format on Same as the original and JPGs stay JPGs, PNGs stay PNGs. Two things to know. JPEG has no transparency, so a transparent PNG saved as JPG is flattened onto white here rather than the black you get by accident elsewhere. And any JPEG you resize is re-encoded, which is a second generation of lossy compression — at quality 90 that is invisible in normal viewing, but resize from your original rather than from a file that has already been through a round trip.
WebP is worth considering for anything going on a website: at the same visual quality it is typically 25–35% smaller than JPEG, and every current browser supports it. PNG is the right choice for screenshots of text, diagrams and anything with hard edges and flat colour, where JPEG's artefacts are obvious and PNG is often smaller as well.
A whole folder at once
Drop in as many files as you like and one setting applies to all of them; the results come back as a ZIP, each keeping its original name with the new extension. Because everything runs in this page, there is no upload wait, no queue, no per-file size cap and no daily limit — a batch of forty raw exports is limited only by your device's memory and patience. The summary underneath lists what each file was and what it became, so you can check before you unpack the archive.
Common questions
How do I resize a batch of images to the same size?
Drop them all in at once and choose Fit inside a box with the longest side you want. Every image is scaled to that limit while keeping its own proportions, so portrait and landscape photos come out consistent without any of them being stretched. The results download as a single ZIP with the original filenames.
How do I get an image under a specific number of kilobytes?
Use To a file size and type the limit. It searches the encoder's quality settings for the best one that fits, and if even the lowest quality is too big it reduces the resolution and tries again. You get the sharpest image that fits, rather than a guess. The quality slider hides in this mode because the search is what chooses the quality.
Will resizing make my photo blurry?
Making it smaller will not — downscaling averages pixels together and usually looks cleaner than the original, because it hides noise and compression artefacts. Making it larger will, because the extra pixels have to be invented by interpolating between real ones. No tool can recover detail that the camera never captured.
What about DPI — can I set it to 300?
DPI is metadata that says how big to print the pixels; it is not a property of the image and changing it adds no pixels. What matters is total pixels divided by the print size you want: a 4×6 inch print at 300 DPI needs 1200×1800 pixels. Resize to that many pixels here, and set the tag in whatever you print from if it insists on one.
Can I resize without keeping the proportions?
Yes. Choose Exact width and height and untick the shape lock, and the image is stretched to exactly those numbers. With the lock on, which is the default, the image is fitted inside the rectangle instead, so nothing is distorted and one of the two dimensions may come out smaller than you typed.
Which format should I pick?
For photographs on a website, WebP: at the same visual quality it is usually 25–35% smaller than JPEG and every current browser reads it. For photographs going somewhere that might not, JPEG. For screenshots, diagrams, logos and anything with text or hard edges, PNG — JPEG's artefacts are very visible on those and PNG is often smaller for them too.
Is there a limit on file size or number of files?
No. Everything runs in this page using your own device, so there is no upload, no queue, no per-file ceiling and no daily cap. The practical limit is memory: each image is decoded at full size, so a large batch of 40-megapixel photos will run out of room on a phone long before it does on a laptop.
Do my images get uploaded?
No. They are read by the browser's own file API, redrawn on a canvas in this page, and handed straight to your downloads folder. Nothing is sent anywhere, and the page keeps working with your network connection switched off. As a side effect of being redrawn, the output carries no EXIF data, so location and camera details are not passed on.