Resize Image Online

How to resize an image

1. Choose an image, drop it onto the page or paste it from the clipboard. The width and height fields fill in with its current size.
2. Pick Pixels to enter exact dimensions, or Percentage to scale the whole image proportionally.
3. In pixel mode, type the new width. With Keep aspect ratio switched on, the height updates automatically (and the other way round). Switch it off only when you really want to set both values independently; the picture will then be stretched or squeezed.
4. In percentage mode, drag the slider anywhere from 1% to 400%. The line under the controls shows the resulting size in pixels as you move it.
5. Click Resize image, compare the old and new dimensions and file sizes, then click Download resized image. The file name includes the new size, for example holiday-resized-1600x1200.jpg.

How the resizer works

The tool draws your picture onto a canvas of the new size using the browser’s built-in image smoothing, with the “high” quality setting where the browser supports it. When you shrink an image to less than half of its size, it does not jump there in one step. It halves the image repeatedly and makes the final adjustment at the end. A single large jump can skip over pixels and leave jagged edges or shimmering moiré patterns on fine textures; stepping down averages neighbouring pixels at each stage, which gives a cleaner result, similar to what desktop image editors do.

The output keeps the source format whenever the browser can write it:

• JPEG stays JPEG and is saved at quality 92, high enough that the extra compression is hard to see.
• PNG stays PNG, losslessly, including any transparency.
• WebP stays WebP if your browser can encode it; otherwise it is saved as PNG.
• GIF, BMP and other formats are saved as PNG. Animated GIFs keep only their first frame.

Each side can be up to 10,000 pixels. As with every tool on this site, the file is processed locally, and the resized copy is a fresh encode without the original’s EXIF metadata.

Pixels or percentage?

Use pixels when the destination tells you what it needs: “1200 × 630 for link previews”, “at most 2000 pixels on the longest side” for a marketplace listing, or the width of your website’s content column. Use percentage when you simply want the image smaller in proportion. Remember that the effect on pixel count is squared: at 50% each side is halved, so only a quarter of the pixels remain, and the file usually shrinks by a similar large factor.

Tips for sharp, light images

• Resize before you compress. Pixel count drives file size more than any quality setting. Resize to the display size first, then use Compress Image if the file is still too heavy.
• Plan for high-density screens. Phones and many laptops show two or more physical pixels per CSS pixel. An image displayed 600 pixels wide looks crisp on those screens at about 1200 pixels.
• Change the shape by cropping, not by stretching. If you need a square or a 16:9 banner from a photo with a different shape, crop it to that ratio first with Crop Image, then resize. Unlocking the aspect ratio distorts faces and logos.
• Enlarge sparingly. Upscaling adds pixels but no new detail, so anything beyond a modest enlargement looks soft. When you need a bigger image, go back to a larger original if one exists.
• Match the exact size the site asks for. Many platforms resize uploads again on their side. Uploading the size they recommend avoids a second, lower-quality resize done by someone else’s software.

Common reasons to resize

• Meeting upload requirements that state exact pixel dimensions or a maximum width.
• Preparing photos for a website, an online shop or a newsletter template, many of which are around 600 pixels wide.
• Creating thumbnails for galleries, catalogs or video platforms.
• Making phone photos, which are often 4000 pixels or more across, practical to share and store.
• Producing a set of sizes, such as 800 and 1600 pixels wide, for responsive images on a website.

Limitations

• One image at a time; there is no batch processing.
• The output format follows the input. To change the format as well, use PNG to JPG, JPG to PNG or the format option in Compress Image.
• Resampling uses your browser’s own algorithms, so results can differ very slightly between browsers.
• Very large outputs can exceed the canvas memory some mobile browsers allow; the tool shows an error instead of a broken file if that happens.

Frequently asked questions

Related tools

Related guides

• Social Media Image Sizes in 2026: Dimensions, Aspect Ratios and Cropping – Common image sizes for Instagram, Facebook, X, LinkedIn, YouTube and Pinterest as of 2026, safe zones that get covered or cropped, and how to prepare an image in three steps.
• How to Compress Images for Your Website Without Visible Quality Loss – A practical workflow: size images to how they are displayed, pick a format, find the lowest quality that still looks right, and serve the result with the right HTML attributes.