Step-by-step guide: How to Resize an Image Without Losing Quality
How to use the Image Resizer
- Choose an image or drag it onto the box. Its current dimensions and file size are shown.
- Enter a new width or height in pixels. With Keep aspect ratio ticked, the other dimension updates automatically so the image is not stretched.
- Alternatively, switch to Percentage and enter a scale such as 50%.
- Choose the output format and, for JPEG or WebP, the quality.
- Select Resize image, check the preview and new file size, then download.
Example: a banner for a website header
A designer has a 6000 × 4000 px photo and needs a 1600 px wide header image. With aspect ratio locked, entering 1600 for the width sets the height to 1067 px automatically (6000 ÷ 4000 = 1.5, and 1600 ÷ 1.5 = 1066.7, rounded to 1067). Saved as WebP at 85% quality, the result is a small fraction of the original file size.
For social media, common target sizes include 1080 × 1080 px for square posts and 1200 × 630 px for link previews; use the Image Cropper first if the proportions need to change.
When to resize an image
Cameras and phones produce images far larger than most screens display. A 4000-pixel-wide photo shown in a 800-pixel-wide column forces visitors to download five times the pixels in each direction — about 25 times as many in total. Resizing to the size you actually need is the single most effective way to cut image weight, and it also helps when a form, marketplace or profile requires specific dimensions.
How the resizing works
The image is drawn onto a canvas at the new size using the browser’s high-quality smoothing. When shrinking by more than half, the tool halves the image repeatedly and then makes a final step to the exact size. This multi-step approach avoids the jagged, over-sharpened look that a single large reduction can produce.
Enlarging is possible up to 400% or 16,384 pixels per side, but it cannot add detail that was not captured: an enlarged image will look softer. With aspect ratio locked, the missing dimension is calculated from the original proportions and rounded to the nearest whole pixel.
Limitations to keep in mind
- Enlarging an image makes it bigger but not more detailed; expect a softer result.
- Metadata such as EXIF and GPS data is not copied to the resized file.
- Animated GIFs are resized using their first frame only.
- Very large outputs can exceed browser canvas limits, especially on phones; the tool warns you when a size is too large.
How your data is handled
Your image is resized locally in your browser and is not uploaded or stored.
Frequently asked questions
Will resizing reduce quality?
Reducing dimensions keeps images looking sharp at their new size. Repeated resizing of the same file can soften it slightly, so always resize from the original when possible.
How do I resize without stretching the image?
Keep Keep aspect ratio ticked and enter only the width or the height. To change the proportions — for example, to make a square — crop the image instead.
What size should images be for a website?
Match the largest size at which the image is displayed, doubled for high-density screens if sharpness matters. For a full-width hero image, 1600–2400 px wide is common; for in-content images, 800–1200 px is usually enough.
Does the resizer change the file format?
Only if you choose a different format under Save as. By default it keeps the original format, except for GIF and BMP, which are saved as PNG.