Image Resizer

How Image Resizer works

Resize images by exact pixels, a percentage, or the longest edge while keeping the aspect ratio locked. Everything happens inside this page: the tool reads your input, runs the calculation or conversion locally, and hands the result back to you. Nothing is transmitted, because there is no backend to transmit it to.

That design choice is deliberate. Most free tool sites upload your files to a server, process them there, and quietly keep a copy. Toolcin cannot do that — the site is a set of static files. If your connection dropped the moment the page finished loading, every tool would still work.

Three ways to set the size

Width alone is usually enough: type a number, keep “keep ratio” ticked, and the height is calculated from the original proportions so nothing is squashed. Typing a height instead works the same way in reverse.

The percentage field is a shortcut for scaling relative to the original — 50 halves both dimensions, 200 doubles them. Above 100% there is no new detail to find, so the image gets softer; that is inherent to upscaling, not a bug in the tool.

What resizing costs in quality

Downscaling throws pixels away, and the browser's resampler averages neighbourhoods to avoid jagged edges. For a large reduction — 4000 px to 800 px — a single pass is fine for photos but can look slightly soft for fine text or thin line art.

Upscaling cannot invent detail. Doubling a 600 px logo gives a 1200 px file that still looks like a 600 px logo, only bigger. If you need a sharp large version, start from a vector or a larger original.

Which format comes out

The output keeps the input format: a JPEG stays JPEG at quality 0.92, and anything else is written as PNG. That means a transparent PNG keeps its transparency, and a JPEG does not suddenly gain an alpha channel.

If you need WebP or a different quality target, resize first and then run the file through the image converter — two steps, no surprises, and each step reports the resulting size.

Sizes worth knowing

Common targets: 1200 × 630 for a link preview image, 1080 × 1080 for a square post, 1600 px on the long edge for a blog header, 512 × 512 for an app icon. Upload forms often cap at 2 MB or 5 MB, and resizing is usually a bigger win than compressing at the original size.

Good to know

• Works offline once loaded, including on flights and in locked-down networks.
• No file size limit beyond your device's own memory.
• Free to use, with no account and no usage counter.
• Results are produced locally, so they are not logged or shared with anyone.

Questions