How to use the image resizer
- Choose an image. Its pixel size and file size appear under Original.
- Choose Set size in pixels and type a width or a height, or pick a preset. With Lock aspect ratio on, the other side follows. Or choose Scale by percent and type a percentage.
- Pick the output format (PNG, JPG or WebP). For JPG and WebP, set the quality. For JPG, choose a background color for any transparent areas.
- Select Resize image to see the result with its new dimensions and file size, then Download resized image.
How the resize works
Your browser decodes the picture, applies any rotation stored in the photo, and draws it onto a canvas of the new size with high quality smoothing. When an image shrinks by more than half, it is reduced in several steps of at most 2 to 1 instead of one big jump, which keeps fine detail cleaner. The canvas is then encoded as PNG, JPG or WebP. The picture never leaves your device.
Locking the aspect ratio
With the lock on, changing one side sets the other from the original proportions and rounds to the nearest whole pixel. A 400 by 300 image set to 200 wide becomes 200 by 150. Presets then fit the image inside the box of that preset without changing its shape, so the 1920 by 1080 preset gives 1440 by 1080 for that 4 to 3 image. Turn the lock off to enter any width and height, which stretches the picture if the ratio differs. If you need an exact shape without stretching, resize first and then use the crop image tool.
Choosing a format
PNG is lossless and keeps transparency, which suits screenshots and logos. JPG is smaller for photographs and has no transparency, so transparent areas are filled with the background color you pick. WebP can be smaller than both and keeps transparency. Some browsers, notably older Safari versions, cannot create WebP files. In that case the tool tells you and saves a PNG so you never get a file with the wrong name.
Limits
Resizing is memory hungry because the browser holds the full-size pixels, so the tool sets firm limits.
- Input up to 25 MB per file.
- Output up to 16,384 pixels on each side and 120 megapixels in total. Larger requests are refused with a message that shows the numbers.
- Some phones and older browsers cannot allocate canvases near those limits. If yours cannot, you get a message and can choose a smaller size.
- One image at a time. Animated GIFs and WebPs are resized using their first frame only.
- SVG files are drawn at 1024 pixels wide first, then resized. Use the image converter to rasterize an SVG at a specific width.
Quality notes
Making an image larger cannot add detail. The tool allows it, but the result will look soft, and says so. Metadata such as camera model and location is not copied to the new file, because the image is redrawn. This is useful for privacy, but it also means embedded color profiles are dropped. To reduce file size without changing dimensions, use the image compressor.
Assumptions and limits
- The image is processed on your device. Nothing is uploaded or stored.
- Sizes are whole pixels. Computed dimensions are rounded to the nearest pixel and never less than 1.
- Output is limited to 16,384 pixels per side and 120 megapixels. Input is limited to 25 MB per file.
- Metadata, including EXIF location and embedded color profiles, is not carried into the resized file.
- Animated images use their first frame. WebP output depends on browser support, and the tool reports when it falls back to PNG.
Frequently asked questions
How do I resize an image to 1920 x 1080 without stretching it?
Keep Lock aspect ratio on and choose the 1920 x 1080 preset. The image is scaled to fit inside that box, so one side may be smaller than the preset. To fill the box exactly, crop to 16:9 first with the crop tool.
Why did my file get bigger after resizing?
Saving as PNG, enlarging, or choosing a high quality setting can all create a larger file than the original JPG. Pick JPG or WebP and lower the quality, or reduce the dimensions.
What does percent mean here?
It scales both sides by the same factor. 50 percent halves the width and height, which leaves one quarter of the pixels.
Why does the transparent part of my PNG turn white in a JPG?
JPG cannot store transparency, so those areas are filled with the background color you choose. White is the default.
Is there a way to resize many images at once?
This tool handles one image at a time. The image compressor accepts several files and can limit their width in one pass.