Image Resizer

No. Resizing happens entirely in your browser using the canvas element: the image is processed on your own device and never sent anywhere. That is why you can resize private photos, documents or screenshots with sensitive data without them leaving your computer, and it works offline once the page has loaded.

By pixels you set the exact width or height you want (say 800px wide), useful when you have a specific requirement. By percentage you scale relative to the original size (say 50%), handy when you just want it "half as big" without doing the maths. Both keep the aspect ratio if you leave the lock on.

Yes, if you enlarge it a lot. Shrinking an image almost always looks fine, because surplus information is discarded. Enlarging forces the browser to invent pixels that were not there, and the result comes out blurry or pixelated. The rule of thumb is to resize down, not up: always start from the largest original you have.

Almost always yes. With the aspect-ratio lock on, changing the width adjusts the height automatically and the image is not distorted. Only turn it off when you need exact dimensions and do not mind cropping or stretching, which is rare. If you need a fixed size without distortion, the right move is usually to crop, not stretch.

Yes. You can export the result as PNG, JPG or WebP. As a rule, WebP gives the smallest size for the web with good quality, JPG is the safe choice for photographs where you do not need transparency, and PNG is best when the image has a transparent background or crisp text that should not be lossily compressed.