Resizing an image means changing how many pixels it has, by exact dimensions or by percentage. Get it right and your pages load faster and your layouts stay crisp. Get it wrong and you end up with stretched, blurry images. Here is how to resize cleanly and what each setting actually does.
Resize by pixels or by percentage
There are two ways to set a new size, and they solve different problems.
- By pixels: type an exact width or height. Use this when you know the slot the image fills, like a 1200px hero or a 400px thumbnail.
- By percentage: scale to 50% or 25% of the original. Use this when you just want it smaller and do not care about an exact number.
Open the Image Resizer, drop in your file, and pick whichever fits the job.
Lock the aspect ratio to avoid distortion
The aspect ratio is the relationship between width and height. If you change one without the other, the image stretches and people look squashed or stretched.
Keep the ratio locked and set width OR height. The tool fills in the other side automatically so proportions stay perfect. Only unlock the ratio if you genuinely need a specific non-proportional size, and expect distortion when you do.
Downscaling vs upscaling
Direction matters more than most people think.
- Downscaling (making an image smaller) is safe. You are throwing away pixels you do not need, and the result stays sharp.
- Upscaling (making it bigger) cannot invent detail that was never captured. The software guesses at new pixels, so the image just gets softer and blurrier.
The rule: resize down to the size you actually display, and never blow a small image up to fill a large space.
Why resize before uploading
A phone photo can be 4000px wide and several megabytes. If your page only shows it at 800px, you are forcing every visitor to download data they never see. Resizing to the display size first cuts the file dramatically, which means less bandwidth and faster pages, especially on mobile.
Resize, crop, and compress are three different jobs. Resize changes pixel dimensions. Crop trims away parts of the frame. Compress shrinks file size at the same dimensions. You often resize first, then compress.
How to use it
- Open the Image Resizer and drop in your image.
- Choose pixels or percentage.
- Keep the aspect ratio locked, then set the width or the height.
- Confirm you are scaling down to your display size, not up.
- Download the resized image.
Everything happens on a canvas in your browser. Your image is never uploaded, so it stays on your device.
Related tools
- Image Compressor: shrink file size after resizing for even faster loads.
- Image Converter: switch between PNG, JPG, and WebP formats.
- Image Cropper: trim the frame instead of scaling the whole thing.
Resize down to the size you show, keep the ratio locked, and your images stay sharp and light.