Why resize an image
Most photos have far more pixels than they need. A phone photo is often around 4000 pixels wide, while a website column, an email or a form may need a quarter of that. Too many pixels make files heavy and uploads slow, and some forms ask for exact dimensions. Resizing to the size you actually need is often the most effective way to make an image lighter.
How to use it
- Add one image or several.
- Choose a mode and enter the values (see the table below).
- Choose the output: keep the original format, or save as JPG, PNG or WebP. Set the quality slider for lossy formats.
- Download the result, or all images as a ZIP. The old and new dimensions are listed for each file.
Your images are resized by your browser and are never uploaded.
Which mode to use
| Mode | What you enter | Use it when |
|---|---|---|
| Pixels | Width and/or height, with the aspect ratio lock | A form or website asks for exact pixel dimensions |
| Percent | 10 to 400 percent | You want everything half or a quarter of the size |
| Longest side | One value, such as 1920 px | A batch mixes portrait and landscape photos |
| Print size | Width and height in cm, plus a DPI of 72, 150, 300 or 600 | You are preparing a photo for printing |
With the aspect ratio lock on, you enter one side and the other follows, so nothing gets stretched. Turn the lock off only if you really need dimensions with a different shape, and accept that the image will be distorted. To change the shape without distortion, crop first.
Longest side is the handy mode for batches. With 1920 px, a landscape photo becomes 1920 px wide and a portrait photo becomes 1920 px tall, and both keep their proportions.
Print size and DPI
In print size mode, the tool calculates the pixels from the paper size: pixels = centimeters / 2.54 × DPI. A 10 × 15 cm print at 300 DPI needs about 1181 × 1772 px. The tool also writes the DPI value into the file, so programs and print services see the intended size. 300 DPI is the usual target for photo prints; 150 DPI is often enough for posters seen from a distance. Our DPI guide explains this in depth, and the cm to pixels calculator converts sizes without changing a file.
Making images bigger
You can enlarge an image, up to 400 percent in percent mode, but the tool warns you when you do. Enlarging spreads the existing pixels over a bigger area; it cannot add detail that was never captured, so the result looks softer. When you shrink an image a lot, the tool scales it down in several steps, which keeps fine lines and text cleaner than a single jump.
Frequently asked questions
Will resizing reduce the file size?
Making an image smaller in pixels almost always reduces the file size, often a lot. If you need to get under a specific KB limit, use Compress to a target size afterwards.
How do I resize without stretching the photo?
Keep the aspect ratio lock on, or use percent or longest side mode, which always keep the proportions.
Can I resize many photos to the same size at once?
Yes. Add them all, choose the settings once and download the results as a ZIP.
Does changing the DPI make my photo sharper?
No. Sharpness depends on the number of pixels. DPI only tells a printer how large to print them.