Image Resizer
Resize any image to exact dimensions for specific devices and social platforms. 30+ presets including iPhone 15 series, Android devices, Instagram posts/stories/reels, Twitter/X headers, LinkedIn backgrounds, YouTube thumbnails, and OpenGraph images. Use high-quality Lanczos3 resampling — sharper than browser default scaling. Export as JPEG, PNG, WebP, or AVIF.
What does this tool do?
The Image Resizer provides precise dimension control for images destined for specific uses. It offers 30+ presets for popular devices (iPhone 15 Pro, Pixel, Galaxy, iPad), social media (Instagram square/portrait/story, X/Twitter headers, LinkedIn, Facebook), and web (YouTube thumbnails, OpenGraph images, favicons). Custom sizing allows exact pixel dimensions or percentage scaling. The Lanczos3 resampling filter produces sharper results than browser default scaling. Cover mode fills the target exactly (may crop), Contain mode fits within target (may add padding). Output format and quality are configurable.
How it works
Using Canvas API with custom Lanczos3 resampling, the tool decodes the source image, applies the selected resize algorithm, and encodes to the target format. Lanczos3 uses a sinc-based kernel for high-quality downscaling that reduces aliasing better than bilinear or bicubic. For preset modes: the preset provides target width/height, then either Cover (scale to fill, crop overflow) or Contain (scale to fit, preserve aspect) is applied. For custom mode: exact dimensions are used, or percentage scaling applied to original. The resized image is encoded with selected format and quality settings for download.
Features
- 30+ device + social presets: iPhone 15, Pixel, Galaxy, iPad, Instagram, X/LinkedIn/FB, YouTube, OpenGraph
- By-width, by-height, percent, or exact-pixel modes
- Lanczos3 resampling — sharper than browser bilinear/bicubic
- Cover (fill, crop) or Contain (fit) mode
- Output as JPEG / PNG / WebP / AVIF with quality control
- 100% client-side processing
- Filename includes new dimensions
How to use
- 1
Drop an image
Source can be any size or format. Original file is not modified — a new resized version is created.
- 2
Pick a preset or custom size
iPhone 15 Pro, Instagram Story, OpenGraph, etc. — all popular sizes pre-listed. Or enter exact width/height or percentage.
- 3
Choose output format + quality
WebP at 85 is the universal default for web. PNG for lossless. JPEG for maximum compatibility.
- 4
Select Cover or Contain
Cover fills the target exactly, cropping if aspect ratios differ. Contain fits within target, preserving full image (may add padding).
- 5
Download
Filename includes the new dimensions for easy identification (e.g., photo-1080x1920.webp).
Common use cases
Social media optimization
Create perfectly sized images for Instagram posts, stories, Twitter headers, Facebook covers without platform cropping surprises.
Device wallpaper creation
Resize photos to exact device dimensions (iPhone 15 Pro, Galaxy S24, etc.) for perfect wallpaper fit without zooming.
Web asset preparation
Create OpenGraph images (1200×630), favicon sources, and hero images at exact dimensions for clean web implementation.
Thumbnail generation
Resize images for YouTube thumbnails, gallery previews, and catalog listings at consistent dimensions.
Tips & best practices
- Lanczos3 is sharper for downscaling than Canvas drawImage's default bilinear/bicubic. It matches what Photoshop/GIMP produce
- iPhone Pro 'physical' vs 'logical' resolution: presets use physical pixels. iOS reports logical points at 2× or 3×. Our sizes are what you actually need in the file
- Cover mode is best for backgrounds and fills where the image should occupy full space. Contain is best for product photos and logos where nothing should be cut off
- Instagram post: 1080×1080 (square), 1080×1350 (portrait 4:5), 1080×608 (landscape 1.91:1). Story/Reels: 1080×1920 (9:16)