Resize an image

How the size works

You set the longest side and the other side follows, so the picture keeps its shape and nothing is cropped or squashed. A 4,000 by 3,000 photo set to 1,280 comes out 1,280 by 960.

It only ever scales down. Ask for 2,560 on an image that is already 1,600 across and you get the same image back, because enlarging a photograph does not add detail to it, it just adds bytes and softens what was there.

What size should you pick

• 1,280px is a safe default for a photograph on a web page, and what this tool starts on.
• 1,920px if it runs full width on a desktop layout, or if it is a hero image people will look at properly.
• 2,048px for online shops. Shopify and most marketplaces want room to zoom into a product.
• 800px or less for thumbnails, avatars and anything in a grid. The most common mistake on the web is shipping a full-size photograph into a 200px box.

Retina screens are the reason those numbers are larger than the space the image occupies. Roughly double the displayed width is the usual rule, and past that you are paying for pixels nobody sees.

Why resize before uploading

Images are the heaviest thing on almost every page. The 2025 Web Almanac puts the median home page at over a megabyte of images on desktop, which is more than JavaScript and more than fonts. Resizing is the crudest and most effective lever you have on that, and unlike most page speed work it takes seconds.

A content management system that resizes on upload does not make this pointless. It still has to receive the original first, and a 12MB camera file is a slow upload on a phone and a large thing to store. What actually affects your Google rankings has the numbers on where image weight sits in the picture.

Resize, or convert, or both

This tool leaves the format alone by default, so a JPEG stays a JPEG. If you want a smaller file as well as smaller dimensions, change the format to WebP, or use the WebP converter, which is the same tool pointed at the other half of the job. Doing both at once is usually the right answer for anything going on a web page.