Image Resizer
Resize images by dimensions, percentage, or longest edge. Supports JPG, PNG, WebP, GIF, and SVG sources.
Runs entirely in your browser — your image is never uploaded.
About this tool
Resizes images by exact dimensions, percentage, or longest-edge constraint. Useful for shrinking photos for the web, generating thumbnails, or meeting size requirements on online forms. Your image stays on your device — nothing is uploaded.
Resize modes
- Width × height — set exact pixel dimensions. With aspect ratio locked, changing one updates the other proportionally.
- Percentage — scale by a factor. 50% halves dimensions (and quarters file size on photos).
- Longest edge — cap the larger dimension. The shorter dimension scales proportionally. Use this for "max 1920px for web" or "max 800px for email".
Quality settings
When converting to a lossy format (JPEG, WebP), the quality slider controls how aggressively the image is compressed. 85–90% is usually visually indistinguishable from the original. The slider is ignored for PNG (lossless).
Frequently asked questions
- Why does my resized image look soft or blocky?
- You're probably scaling up. Browser canvas uses bilinear interpolation, which is fine for shrinking but creates softness when enlarging. For best results, start with a higher-resolution source. There's no way to add detail that wasn't there.
- How is "longest edge" different from "width × height"?
- Longest-edge mode picks the larger of width and height and resizes that to your target, scaling the other dimension proportionally. So a 4000×3000 photo with longest-edge=1920 becomes 1920×1440. A 3000×4000 photo with the same setting becomes 1440×1920. Width × height mode requires you to specify both numbers.
- Does this preserve transparency?
- For PNG and WebP output: yes. For JPEG output: no (JPEG doesn't support transparency, so transparent areas become white).
- Can I resize a 50 MB image without crashing my browser?
- Probably. Modern browsers handle 100+ megapixel images in canvas with care. Very large images may take a few seconds to load and resize.
- What about SVG input?
- SVG is supported as input — it's rasterized at the output size you specify, which is one of the advantages of vector source files. You can't output to SVG from a raster image, though (that would require vectorization).
Last updated: May 17, 2026