We measured it: real file sizes
Settings: resized to 800 px wide, aspect ratio locked
What the numbers sayGoing from 1200 px to 800 px wide removes 56% of the pixels — but the files only shrank 15% to 50%. The photo halved (1.88 MB to 967.2 KB) while the screenshot gave up just 15%, because its cost is in the sharp edges, and shrinking keeps every one of them. Fewer pixels is not proportionally fewer bytes.
Measured on 2026-07-28 by running these files through this very page in Chromium 151.0.7922.34. Every page uses the same published test files, so the numbers are comparable across converters.Method, and download the test images →
What is image resizing?
Resizing means changing the pixel width and height of an image — for example shrinking a large phone photo to an upload-friendly size, or fitting a social/avatar spec. This tool resizes locally in your browser: no upload, fast and private.
How to use it
- Drop in or select an image; the tool shows its original dimensions.
- Enter a target width or height (with the ratio locked, the other side is filled in automatically).
- Click Download to save the resized image.
Common uses and tips
- Websites/e-commerce: shrink oversized originals to their actual display size to load much faster.
- Social/avatars: resize to the platform’s recommended size first to avoid auto-cropping or blurring.
- To also cut the file size, resize first, then run the result through the image compressor.
Cut the pixel count in half — why don’t the bytes follow?
Put the arithmetic on the table first. All four files were resized to the same target, 800 × 533, from 1200 × 800 — a drop of 56% in pixels. The bytes ignore that ratio completely. The photo, 1.88 MB → 967.2 KB (-50%), roughly keeps up. The UI screenshot manages only 18.0 KB → 15.3 KB (-15%). The illustration lands at -17% and the transparent logo at -40%, so the four results spread from -15% to -50%. The outputs are the stranger half: four files with identical dimensions range from 15.3 KB to 967.2 KB, a 63× spread. Dimensions set a ceiling, not a cost. The cost is how unpredictable each pixel is: a screenshot is mostly flat and already compressed well, so shrinking recovers little, while every pixel of a photograph is different and each one you drop is real data gone.
Frequently Asked Questions
I halved the width. Why is the file not half the size?
Because bytes do not follow pixels. Going from 1200 px to 800 px wide removes 56% of the pixels, but our files only shrank between 15% and 50%: the photo halved, from 1.88 MB to 967.2 KB, while the UI screenshot gave up just 15%, from 18.0 KB to 15.3 KB. A screenshot costs bytes at its sharp edges, and shrinking keeps every one of them.
Are my images uploaded?
No. Resizing runs entirely in your browser using the Canvas API. Your images are never sent to a server or stored.
Is the aspect ratio kept?
By default the aspect ratio is locked: change one side and the other is calculated proportionally to avoid stretching. You can unlock it to set width and height freely.
Can I enlarge an image?
Yes, but enlarging cannot invent detail — stretched pixels may look soft or jagged. For crisp scaling-up, a vector (SVG) or an AI upscaler is a better fit.
Does downscaling reduce quality?
Downscaling is usually clean with little visible loss. The output keeps the original format; if the source is JPG it is still lossy, so only repeated re-saving degrades it over time.
