Image Resizer
Resize, crop and rotate images with pixel-perfect control — by exact dimensions, a percentage, or a preset size, with high-quality Lanczos resampling. Everything runs in your browser; your files are never uploaded.
Tip: paste with Ctrl/⌘ + V · everything is processed on your device — nothing is uploaded.
How to resize an image online
- 1
Drop, browse, or paste an image (PNG, JPG, WebP, HEIC or BMP).
- 2
Optional: turn on Crop, pick an aspect ratio and drag the box — or rotate and flip the image.
- 3
Resize by percentage, exact dimensions, or a preset size; keep "Lock aspect ratio" on to keep proportions.
- 4
Choose a resampling method (Lanczos is sharpest), a fill mode, and add sharpening if you upscaled.
- 5
Pick an output format and quality (or PNG color depth), then download — the new size updates live.
About the Image Resizer
Resizing images is one of the most common tasks on the web — shrinking a photo so it uploads faster, fitting an image to exact dimensions for a website or social post, or scaling artwork up. iResize gives you pixel-perfect control with high-quality Lanczos resampling, aspect-ratio locking, fit modes and live previews. Because it runs entirely in your browser there are no upload limits and your photos stay completely private.
When you'll reach for an image resizer
Resizing is one of those small jobs that comes up constantly. You might be shrinking a photo so it uploads under a website's pixel limit, fitting an image to the exact dimensions a profile or banner demands, scaling a screenshot down for documentation, or enlarging artwork for a print. In every case the goal is the same: change the dimensions without ruining how the image looks. This resizer gives you three ways to do that — by an exact width and height in pixels, by a percentage of the original, or with a preset — so you can match whatever a form or platform asks for.
Getting the sharpest result
How an image is scaled matters as much as the size you pick. For making images smaller, Lanczos resampling keeps edges and fine detail crisp where a naive scale would look soft or jagged — it's the default here for that reason. Keep Lock aspect ratio on so the picture doesn't stretch; turn it off only when you deliberately want to squash or stretch to fit. Enlarging is the harder direction: no tool can invent detail that isn't there, so an upscaled image will always be a little softer than a native one. A touch of sharpening after upscaling helps recover apparent crispness without overdoing it.
Choosing an output format
When you export, the format decides the trade-off between size and fidelity. WebP usually gives the smallest file at good quality and is ideal for the web; JPG is the safe, universally compatible choice for photographs; and PNG keeps transparency and is lossless, which suits logos, icons and screenshots with text. If you need to also bring the file size down to a specific number afterward, hand the result to the image compressor. Everything here runs in your browser, so even large images are resized instantly and never leave your device.
Frequently asked questions
Are my images uploaded to a server?
No. All resizing happens locally in your browser using the Canvas API. Your files never leave your device, so it is completely private.
Which image formats are supported?
You can resize PNG, JPEG, WebP and BMP images, and export to PNG, JPEG or WebP.
Will resizing reduce the quality of my image?
Making an image smaller keeps quality high. Enlarging beyond the original size can soften details, since no new pixels can be invented. For JPEG and WebP you can also choose an output quality.
Is there a file-size limit?
There is no fixed limit, but very large images depend on your device's memory. Most photos resize instantly.
Does it keep the aspect ratio?
Yes. Aspect-ratio lock is on by default, so changing the width updates the height automatically. You can turn it off to stretch freely.
Can I resize an image to exact pixel dimensions?
Yes. Switch to exact dimensions and type a width and height in pixels. With aspect-ratio lock on, the other value follows automatically; turn it off to set both independently.
How do I resize without losing quality?
Making an image smaller keeps quality high, especially with Lanczos resampling. Avoid enlarging beyond the original where you can, and export to PNG (lossless) or a high JPG/WebP quality to preserve detail.