📐 Image Resizer
Resize images by exact pixels, percentage, centimetres or inches — with 16 social media presets and aspect ratio lock. Canvas API processing, no uploads.
Drop an image here or click to upload
JPG, PNG, WebP — single image
About This Image Resizer
An image resizer is a browser-based tool that changes the pixel dimensions of an image — used by photographers, social media managers, web developers and designers to match images to specific size requirements. This image resizer processes files client-side using the HTML5 Canvas API, with four resize modes, 16 platform presets and aspect ratio lock.
This image resizer delivers four distinct ways to control output dimensions: exact pixels for technical requirements, percentage for proportional scaling, centimetres for physical print dimensions, and inches for North American print standards. Switch between modes using the tabs in the settings panel — the dimension inputs update automatically and the aspect ratio lock carries across all four modes.
The social media preset selector covers 16 common sizes across Instagram, Facebook, Twitter/X, LinkedIn, YouTube and WhatsApp. Selecting a preset fills the width and height fields instantly — no manual specification lookup needed. For print work, the DPI selector converts physical measurements to the correct pixel dimensions: 72 DPI for web graphics, 150 DPI for medium-quality print, and 300 DPI for professional print output where fine detail must be preserved.
According to HTTP Archive data, images account for roughly 45% of an average webpage's total byte weight — resizing to the exact display dimensions before upload eliminates wasted bandwidth from oversized originals and improves Core Web Vitals LCP scores directly. This image resizer produces output via the browser's native canvas.toBlob() method with no server round-trip.
Aspect ratio lock is enabled by default: adjusting width recalculates height automatically, and vice versa. Disable it to set width and height independently — required when fitting to a fixed social media canvas where both dimensions are mandatory regardless of the source image's proportions.
How to Use This Image Resizer
How the Image Resizer Works Step by Step
- Upload a JPG, PNG or WebP image using the upload area, or drag it directly onto the zone
- Select your resize mode — Pixels, Percentage, CM or Inches — using the four tabs in the settings panel
- Enter your target width and height, or pick a social media preset from the dropdown to fill both fields in one click
- Click Resize Image and download the output file — the resized image is generated in your browser using the Canvas API
Use image compression after resizing to reduce file size further — a correctly resized image still benefits from compression before upload to social media platforms or a CMS. For print work in CM or Inches mode, select 300 DPI to produce sufficient pixel density for sharp physical reproduction at small type sizes.
Social Media Preset Dimensions Reference
| Platform & Type | Dimensions |
|---|---|
| Instagram Post | 1080 × 1080 px |
| Instagram Story / Reel | 1080 × 1920 px |
| Facebook Post | 1200 × 630 px |
| Facebook Cover | 851 × 315 px |
| Twitter/X Post | 1200 × 675 px |
| Twitter/X Header | 1500 × 500 px |
| LinkedIn Post | 1200 × 627 px |
| LinkedIn Cover | 1584 × 396 px |
| YouTube Thumbnail | 1280 × 720 px |
| YouTube Channel Art | 2560 × 1440 px |
| WhatsApp Profile | 640 × 640 px |
Who Is This Image Resizer For
An image resizer is used across photography, publishing, social media and web development. These are the groups that reach for one most often:
- Social media managers use preset dimensions to ensure images match each platform's published specifications — incorrect sizes trigger automatic cropping by the platform that can remove faces or text from the composition
- Photographers resize images before delivery to clients — typically to web-safe dimensions like 2048px on the long edge, or to precise print dimensions in centimetres at 300 DPI using this image resizer's physical unit modes
- Web developers and SEO teams resize images to exact display dimensions before uploading to WordPress or other CMS platforms, eliminating browser-side scaling that adds rendering overhead and contributes to poor LCP scores
- E-commerce teams standardise product image dimensions — typically 800×800 or 1200×1200 — to prevent layout shifts in product grids and ensure uniform display across all product listings
- Graphic designers use the centimetres and inches modes to prepare images for print templates at specified DPI values without requiring desktop software to be installed
Explore all our Image Tools for compressing, converting, cropping and colour-extracting from images.
Frequently Asked Questions
What is an image resizer?
An image resizer is a browser-based tool that changes the pixel dimensions of an image. This image resizer processes images entirely client-side using the HTML5 Canvas API — no file is uploaded to any server. It supports resizing by exact pixels, percentage, centimetres or inches, and includes 16 social media presets for Instagram, Facebook, Twitter/X, LinkedIn, YouTube and WhatsApp.
How does the image resizer process images?
The image resizer draws your image onto an HTML5 Canvas element at the target dimensions using drawImage(), then exports the result via canvas.toBlob(). For CM and Inches modes, physical dimensions are converted to pixels using your chosen DPI value: pixels = centimetres × (DPI ÷ 2.54), or pixels = inches × DPI. The entire operation runs in your browser with no server involvement.
Is this image resizer free to use?
Yes. This image resizer is completely free with no signup required and no watermarks applied to output files. All processing happens in your browser — your image never leaves your device. There are no file size limits or usage restrictions beyond what your browser's Canvas API supports (typically up to 16,384 × 16,384 pixels).
Who typically uses an online image resizer?
Social media managers use preset dimensions to match each platform's specifications. Photographers resize images before delivery or print. Web developers and SEO teams resize to exact display dimensions to improve page load times and Core Web Vitals. E-commerce teams standardise product image dimensions. Graphic designers use the CM and Inches modes for print preparation at specific DPI values without installing desktop software.
What are the limits of this image resizer?
The image resizer accepts JPG, PNG and WebP inputs. Canvas output is limited by browser memory — most browsers support up to 16,384 × 16,384 pixels, though performance degrades above 8,000px on either axis. Upscaling a small image to a very large canvas (such as 2560×1440 YouTube Channel Art from a 400px source) will produce visible pixelation because the Canvas API cannot recover detail that was not in the original file.
What social media image sizes does this resizer support?
This image resizer includes 16 built-in presets: Instagram Post (1080×1080), Story (1080×1920), Landscape (1080×566); Facebook Post (1200×630), Cover (851×315), Profile (180×180); Twitter/X Post (1200×675), Header (1500×500), Profile (400×400); LinkedIn Post (1200×627), Cover (1584×396), Profile (400×400); YouTube Thumbnail (1280×720), Channel Art (2560×1440); WhatsApp Profile (640×640), Status (1080×1920).
How do I resize an image to centimetres or inches?
Select the CM or Inches tab in the image resizer, enter your physical dimensions, then choose a DPI from the dropdown. The tool converts using: pixels = centimetres × (DPI ÷ 2.54) for CM mode, or pixels = inches × DPI for Inches mode. Choose 72 or 96 DPI for screen output, 150 DPI for medium-quality print, or 300 DPI for professional print where detail matters.