What is an Image Resizer?
An image resizer changes the pixel dimensions of a picture: for example scaling a 4000×3000 photo down to 1200×900 for a website hero or a marketplace listing.
Resizing happens on a canvas inside your browser with high-quality scaling. Nothing is uploaded, and the aspect-ratio lock prevents accidentally stretched images.
Common targets worth knowing: 1200x630 for social link previews, 1920px wide for full-width website heroes, 800px for blog inline images, 400px for thumbnails. Serving an image at the size it is actually displayed is one of the biggest and easiest page-speed wins: browsers download every pixel you ship, not every pixel they show.
Supported formats
- JPG / JPEG
- PNG
- WebP
Sizing for high-density screens
The number you need is not the size of the slot on the page. Most phones and laptops now pack two or three device pixels into each CSS pixel, so an image displayed in a 600 pixel wide column looks soft unless the file itself is around 1200 pixels wide. Export at roughly twice the display width, then compress harder to pay for it: a 1200 pixel image at quality 70 usually beats a 600 pixel image at quality 90, both in appearance and in bytes.
There is a ceiling. Beyond about twice the display size the extra pixels stop being visible and only cost download time, so three times is worth it for logos and line art on very dense displays and rarely for photographs.
Frequently asked questions
What size should product photos be?
Most marketplaces want 1000-2000px on the long side. Amazon asks for at least 1000px for zoom; keep the original safe and resize copies down.
Does resizing reduce file size too?
Dramatically: halving both dimensions cuts pixel count to a quarter. For the smallest result, resize to display size here, then run the output through the Image Compressor.
Will resizing distort my image?
Not with the aspect-ratio lock on (the default). Unlock it only when you deliberately want an exact width and height.
Can I enlarge an image?
Yes, but upscaling cannot invent detail: a small image enlarged a lot will look soft.
Is the image uploaded anywhere?
No: resizing runs entirely in your browser.
What format is the output?
The same format as the input, so a PNG stays PNG and a JPG stays JPG.