How resizing works here
Resizing changes the pixel dimensions of an image. A photo that is 4000 x 3000 pixels can become 1600 x 1200 pixels, which is the same picture with fewer pixels across and down. The file usually gets smaller at the same time, because there is less data to store.
Two inputs control the result: the target size and the aspect ratio. The aspect ratio is the relationship between width and height. A 3:2 photo stays 3:2 only if both numbers change by the same factor. Keep the lock on and typing a new width updates the height automatically. Turn the lock off when you need an exact, non-proportional size, such as a square crop for a profile picture.
Pixels or percentage
Pixel mode is for exact targets. Use it when a site or form states a required size, like 1200 x 630 for a social share image.
Percentage mode scales the whole image by a factor. Entering 25 gives a quarter of the original width and height, so a 2000-pixel-wide photo becomes 500 pixels wide. This is the quickest way to shrink a batch of photos that all need the same relative reduction.
Batch resizing
Drop several files at once and they queue up in the list. Set one width and height, or one percentage, and apply it to the whole queue. This is useful for a set of product photos shot on the same camera, or a folder of images that all need to fit the same layout. Each file keeps its own aspect ratio when the lock is on, so mixed portrait and landscape shots both come out correct.
Why enlarging makes images soft
An image holds a fixed number of pixels. Enlarging does not create new detail; the software has to guess the colour of every new pixel by looking at its neighbours. The result looks softer and blurrier than the original, and the file gets larger at the same time. A small amount of enlargement, up to roughly 10-20 percent, is often hard to notice. Beyond that, the softening becomes visible, especially in fine textures and text. If you need a much larger version, start from the largest original you have rather than enlarging a small copy.
Shrinking is the safer direction. Removing pixels is a straightforward calculation, and a photo reduced to fit a screen or a thumbnail usually looks clean.
Recommended pixel sizes
| Use | Typical size (pixels) |
|---|---|
| Social share image | 1200 x 630 |
| Full-width website hero | 1600-1920 wide |
| Blog post image | 1200 wide |
| Profile picture | 400 x 400 |
| Email header | 600 wide |
| Thumbnail | 150-300 wide |
These are starting points, not fixed rules. Check the requirements of the place where the image will appear, and match the longest side to that figure.
What to expect from the file
A phone photo is often 2-5 MB and several thousand pixels wide. Resizing it to 1200 pixels wide for a web page usually brings it well under 1 MB, and often to a few hundred kilobytes. The exact figure depends on the content: a busy scene with lots of detail compresses less than a plain background.
Resizing and compression are separate steps. This tool changes dimensions; saving as JPEG or WebP applies compression on top. If you need a specific file size, resize first, then adjust the quality setting when you save. Check the preview before downloading, since the on-screen result is what you will get.
Working offline and in private
The page runs entirely in your browser. Images are never uploaded to a server, nothing is stored, and there is no sign-up and no watermark. Once the page has loaded, it keeps working without an internet connection, so you can resize photos on a plane or on a locked-down machine.
Questions
Does resizing an image reduce its quality?
Shrinking an image removes pixels and usually looks clean. Enlarging makes it softer, because the extra pixels are estimated from the ones already there. Keep enlargement small, or start from a larger original.
How do I resize an image without stretching it?
Leave the aspect ratio lock on. Then changing the width updates the height by the same factor, so the proportions stay the same. Turn the lock off only when you deliberately want a different shape.
Can I resize several photos at once?
Yes. Drop multiple files into the tool and they queue up. Set one width and height, or one percentage, and apply it to the whole batch, then download the results.
What pixel size should I use for a website image?
A width of 1200 to 1600 pixels covers most blog and content images, and 1600 to 1920 pixels suits a full-width hero. Match the longest side to the widest space the image will fill.