Social Media Image Resizer

No. The file is read directly by your browser and drawn onto a canvas on your own machine. Nothing is sent to Social Magnum or any other server. Which is also why the tool keeps working if you go offline after the page loads.

Cropping a wide photo to a 9:16 story throws away most of the width, and every other resizer decides which part to keep by centring. Click or drag anywhere on your image to pin the part that matters, a face, a product, a logo, and every selected size re-crops around it. The image above dims everything that is about to be cut, so you can see the result before you download it rather than after.

Tick every size you need, or a whole network's worth, and download once. Each copy is rendered independently from your original at exactly the platform's pixel dimensions, then the lot arrives as a single ZIP with the files named by platform and size.

1080×1350 (4:5 portrait) takes the most vertical space in the feed and is the best default. Use 1080×1080 for a square and 1080×1920 for stories and reels.

Crop fills the whole frame and cuts whatever does not fit. What you want almost always, because a padded post looks like a mistake in a feed. Fit keeps the entire image and pads the edges with a colour you choose, which is the right call for logos, screenshots and anything where losing an edge would lose meaning.

Use Blur fill. A 16:9 photo forced into a 9:16 story keeps only about a third of its width, which is why a straight crop so often slices the subject in half. Blur fill puts your whole image in the middle at full width and fills the space above and below with a soft, blurred copy of the picture itself. Nothing is cropped, and it reads as a deliberate design rather than a letterbox.

The tool tells you before you download. Any size that keeps less than about half the picture, or that has to enlarge your original, is labelled with exactly how much, and the big preview shows the crop. If a size is too destructive, switch that batch to Blur fill or Fit.

Scaling down is lossless in practice. Scaling up is not. If your source is smaller than the target size the tool will still produce the file, but it cannot invent detail that was never captured, so it labels the size with how far it is being enlarged. Start from the largest original you have.

JPG at 90–95% quality for photographs, PNG when you need a transparent background or crisp text and flat colour, WebP when you want the smallest file and only care about modern browsers. JPG cannot store transparency at all, so if your image has a transparent background choose the colour it should sit on, or export PNG instead.

Every platform re-compresses what you upload; you cannot stop that, but you can avoid compressing twice. Export at 90–95% rather than 100%, the file is far smaller and the difference is invisible, and always resize from your original, never from something you already exported.