Image Resizer Online — Resize Images by Dimensions or Percentage
The free Image Resizer resizes any JPEG, PNG, or WebP image entirely in your browser — by exact pixel dimensions or by percentage — and downloads the result instantly. No files are uploaded to any server.
Why Image Size Matters
Page load speed is one of the strongest signals in search engine ranking, and images are the dominant contributor to page weight. Google's Core Web Vitals — specifically Largest Contentful Paint (LCP) — measure how quickly the largest visible element loads. Oversized images fail this metric.
The correct resolution for a web image is not the maximum the camera can produce — it is the maximum the layout will ever display. A hero image that renders at 1200px wide does not benefit from being 4000px wide; the browser scales it down anyway, but the user downloads four times as much data.
Resize by Dimensions vs by Percentage
| Mode | Input | Best for |
|---|---|---|
| By dimensions | Target width and/or height in pixels | Fitting images to a specific layout slot (e.g. 1200×630 OG image) |
| By percentage | Scale factor (e.g. 50%) | Reducing file size proportionally without knowing the target resolution |
How to Use the Image Resizer
- Open the Image Resizer.
- Drag and drop an image onto the upload zone, or click to select a file.
- Choose By Dimensions or By Percentage.
- Enter your target width, height, or scale factor. Enable Lock Aspect Ratio to prevent distortion.
- Select the output format (JPEG, PNG, or WebP) and adjust quality if needed.
- Click Download to save the resized image.
Aspect Ratio Locking
When aspect ratio locking is enabled, changing the width automatically recalculates the height to maintain the original proportions, and vice versa. This prevents the distortion that occurs when an image is stretched to a non-proportional size.
Disable aspect ratio locking only when you need a specific output size regardless of distortion — for example, when generating thumbnails that must fit an exact slot (like 400×400 avatar images where cropping is preferable to distortion, but resizing is acceptable).
Choosing the Right Output Format
| Format | Compression | Transparency | Best for |
|---|---|---|---|
| JPEG | Lossy | No | Photographs, hero images, product photos |
| PNG | Lossless | Yes | Screenshots, logos, icons, text-heavy images |
| WebP | Lossy or lossless | Yes | Web images — smaller than JPEG/PNG at equivalent quality |
WebP is the recommended format for modern web use. It produces files 25–35% smaller than JPEG at equivalent visual quality. Browser support is universal as of 2023. The only reason to prefer JPEG is compatibility with older systems or upload targets that do not accept WebP.
Common Size Targets
- Open Graph / social sharing — 1200×630px (Facebook, LinkedIn, Twitter/X)
- Twitter card — 1200×628px or 800×418px
- Avatar / profile photo — 400×400px
- Blog hero image — 1200×675px (16:9)
- E-commerce product image — 800×800px or 1000×1000px (1:1)
- Thumbnail — 300×200px or 400×300px (3:2)
Privacy: No Uploads, No Storage
The Image Resizer uses the browser's Canvas API to perform all resizing on your device. The image bytes never leave your browser — nothing is sent to a server, nothing is stored, and the tool works without an internet connection after the page has loaded.
Resize Your Image Now
Drop an image, set your target dimensions or percentage, choose a format, and download — all in the browser with no uploads.
Open Image Resizer