About Resize Image
Change an image's pixel dimensions with high-quality resampling — bicubic for downscaling, Lanczos-style for upscaling. SnapToolz' Image Resize is built on the Canvas API and a small WebAssembly resampling helper so the output stays sharp even at aggressive resize ratios. Resize by pixels (set exact width/height with optional aspect-lock), by percentage (50% / 25% / custom), or to common presets (thumbnail / web / print). Batch supported — drop dozens of images and they all process with the same settings. Output is JPG or PNG. Files never leave your device.
- No uploads
- Browser-only
- Works offline
- 100% free
How it works
- 1
Drop your images
Single image or batch. JPG, PNG, WebP supported. Originals stay untouched on your disk.
- 2
Pick a resize mode
Pixels (exact width × height with aspect-lock), percentage (50% / 25% / custom), or preset (thumbnail / web / print).
- 3
Convert and download
Single image = direct download. Batch = ZIP archive with all resized files. Output format follows the input by default.
Related tools
Browse allShrink JPEG, PNG, and WebP without visible quality loss.
Convert between PNG, JPG, and WebP in seconds.
Crop with aspect-ratio presets — square, 16:9, portrait, freeform.
Convert images to common social aspect ratios with crop, pad, or blur fill.
Frequently asked questions
Are my files uploaded to a server?
No. Every tool on SnapToolz runs entirely inside your browser using JavaScript and WebAssembly. Your file is read locally, processed in memory, and the result is offered as a download. Nothing is sent to a server — there isn't one to send to.
Will resizing reduce quality?
Downsizing is essentially lossless if you stay at or below the source resolution — the resampler picks the cleanest pixels available. Upsizing past the source resolution can't add detail (the data isn't there), so for upscaling beyond ~2×, results soften noticeably.
How do I keep the aspect ratio?
Aspect-lock is on by default — set either the width OR the height and the other adjusts automatically. Click the lock icon to unlink and produce squashed/stretched output (rarely what you want, but available when needed).
What if I just want to compress, not resize?
Use Compress Image instead — it keeps the original dimensions and just optimises the encoding. Resize is for when you need different pixel dimensions (e.g. for an upload size limit, or generating thumbnails).
Does it work offline?
Yes. SnapToolz is a Progressive Web App. After your first visit, the app is cached on your device and every tool keeps working without an internet connection.
Is SnapToolz free?
Yes — every tool is 100% free with no sign-up, no watermark, no hidden tier. The whole platform is open source and we have no plan to gate features.