Image Resizer
Drop an image, choose a size, and download it — without uploading anything.
Drop a PNG, JPEG, WebP or GIF on the left. Astra reads it, resizes it and encodes the copy here — the file never leaves this tab.
01 Capability
What it does
Small details that make the job quicker.
- Fits the image inside the width and height you set, keeps the proportions, and never upscales by accident — a 600px photo stays 600px instead of turning soft.
- Shows the real before and after: pixels, bytes and the difference — smaller or larger — with a preview of the encoded result rather than a scaled-down copy of the original.
- Encodes WebP, JPEG or PNG in the tab, fills JPEG transparency with white, and says plainly when a browser has to fall back to PNG.
- Reads PNG, JPEG, WebP and GIF files, including the first frame of a GIF, and names the exact file that will be downloaded.
- One image at a time, no queue and no account. The file is never uploaded, copied to a server or kept after the tab closes.
02 Questions
Questions
Short answers, no small print.
Does the image get uploaded?
No. The file is decoded, drawn on a canvas and encoded again inside this browser tab. There is no upload, no server, no storage bucket and no analytics event that contains your picture. Close the tab and it is gone.
Why did my image not grow when I set a larger box?
With the ratio locked, the tool fits the image inside the box and never enlarges it. A 600px photo stays 600px inside a 1280px box, which protects it from blur. Unlock the ratio and type the exact pixels if you really need a bigger file, and expect it to look softer.
Which format should I choose?
WebP is the best default for photographs: it is usually the smallest and every current browser reads it. JPEG is the safe choice for older software and email. PNG is lossless and keeps transparency, which makes it right for logos and screenshots; the quality dial does nothing for PNG.
Why is my download a PNG when I picked WebP?
Some browsers can decode WebP but cannot encode it from a canvas. When that happens the tool makes a PNG instead and says so in the result panel, so you are never surprised by a file that does not match its name. The download extension always matches the real file type.
What happens to transparent areas?
PNG, WebP and GIF can carry transparency, and it survives the resize. JPEG cannot, so the tool fills transparent areas with white before encoding instead of leaving them black. If the background matters, choose PNG or WebP.
Can I resize several images at once?
Not here. One image at a time keeps the page fast and the memory predictable, and the file never leaves your device. For a batch, resize the biggest images first; that is where the bytes and the loading time are.