Pixel dimensions (width × height) define how many individual dots make up an image. Physical print size depends on both pixel dimensions and DPI (dots per inch). A 1200×1200 px image at 300 DPI prints at 4×4 inches; the same file at 72 DPI would be 16.7×16.7 inches on screen. For web use, only pixel dimensions matter — DPI metadata is irrelevant in browsers.
Thay đổi Kích thước
Thay đổi Kích thước Chính Xác
Thay đổi kích thước ảnh sang bất kỳ kích thước nào. Pixel, phần trăm hoặc tỷ lệ.
Mọi kích thước
Giữ tỷ lệ
Xử lý hàng loạt
Thả file của bạn vào đây
hoặc hoặc chọn file
JPG, PNG, WebP, GIF • Up to 100 MB
Quick Presets
px
px
Output: —
Đang chờ tải lên...
Chuyển đổi thất bại
Chuyển đổi thất bại
An toàn & Bảo mật
Xóa file sau 2 giờ
Xử lý nhanh
Không cần tài khoản
Cực Nhanh
How to Convert
Chuyển đổi bất kỳ file nào trong vài giây — không cần phần mềm, không cần đăng ký.
01
Tải lên
Tải lên file âm thanh
02
Chọn định dạng
Chọn định dạng đầu ra
03
Tải xuống
Nhận file đã chuyển đổi
Tại sao EasyConv
Why Use EasyConv
Professional-grade conversion with features designed for real-world workflows.
Kiểm soát chất lượng
Điều chỉnh cài đặt chất lượng.
Percentage Scaling
Scale down to 50% or up to 200% of the original size without worrying about exact pixel counts.
Aspect Ratio Lock
Lock the aspect ratio so entering one dimension automatically calculates the other — no stretching.
Không mất dữ liệu
Không mất chất lượng khi chuyển đổi.
Upscale & Downscale
Make images larger or smaller. Downscaling uses Lanczos resampling for the sharpest results.
Xử lý an toàn
File được xử lý an toàn và bảo mật.
300+ Định dạng
Supported Formats
Detailed breakdown of every format supported by this converter.
| Format | Description | Extension | Use Case |
|---|---|---|---|
| JPG | Resized JPEG with quality control | .jpg |
Web photos, email attachments, social posts |
| PNG | Lossless resized PNG with transparency | .png |
UI assets, logos, screenshots |
| WEBP | Resized WebP for optimal web delivery | .webp |
Website images, Next.js Image optimization |
| GIF | Resize static or animated GIFs | .gif |
Animated thumbnails, icon sets |
| BMP | Lossless bitmap resizing | .bmp |
Windows desktop backgrounds, legacy apps |
| TIFF | High-fidelity TIFF resize for print | .tiff |
Print production, archival images |
3 Bước Đơn giản
Frequently Asked Questions
Everything you need to know about this conversion tool.
Yes — enable the aspect ratio lock. When you enter a width, the height is calculated automatically to maintain the original proportions.
You can resize up to 10,000 × 10,000 pixels. Very large upscaling may reduce sharpness — for AI-powered upscaling with detail enhancement, use our Image Upscaler tool.
Single-file resizing is available for free. Bulk resizing via API or batch mode is available for registered users on the Pro plan.
We use Lanczos resampling for downscaling (sharpest results) and bicubic interpolation for upscaling, giving smooth results without jagged edges.
By default the output is the same format as your input. You can also choose a different output format in the options panel.
Common presets: Instagram post 1080×1080, Twitter header 1500×500, Facebook cover 820×312, LinkedIn banner 1584×396. Enter these exact values in the width and height fields.
12M+ người dùng tin tưởng
Who Uses This Tool
Real-world use cases from professionals across different industries.
Social Media Manager
Resize for Social Platforms
Quickly resize photos to exact Instagram, Twitter, Facebook, or LinkedIn dimensions without distortion using the aspect ratio lock.
Web Developer
Generate Responsive Breakpoints
Create 1x, 2x, and 3x versions of the same image for responsive srcset attributes and retina display support.
E-commerce Seller
Standardise Product Thumbnails
Resize product images from varied camera sizes to a uniform 800×800 or 1000×1000 for consistent product listing grids.
Email Marketer
Size Images for Email Templates
Resize images to your email template width (typically 600px) before embedding to prevent broken layouts in Gmail and Outlook.
App Developer
Create App Icon Sizes
Resize a master icon to all required iOS and Android sizes (1024px, 512px, 192px, 144px etc.) in quick succession.
Designer
Resize Mockups for Presentations
Scale mockup images to exact slide dimensions (1920×1080, 1280×720) so they fill your PowerPoint or Keynote perfectly.
Tại sao EasyConv
So sánh
Xem cách chúng tôi so sánh với các giải pháp khác
| Feature |
Our Tool EasyConv |
Photoshop | Other Online |
|---|---|---|---|
| Chất lượng | |||
| Percentage scaling | Varies | ||
| Khóa tỷ lệ khung hình | Varies | ||
| Giữ độ trong suốt | Varies | ||
| Thu nhỏ Lanczos | |||
| Không cài đặt | |||
| Tự động xóa file (2h) | Varies | ||
| API access | Pro |
Technical Specifications
Technical Specifications
Detailed technical information about our conversion engine.
Limits
- Max file size: 100 MB (free)
- Max output resolution: 10,000 × 10,000 px
- Max upscale: 200% (use AI Upscaler for beyond 200%)
Pillow
Lanczos
bicubic
JPEG
PNG
WebP
GIF
Engine
Pillow 10.x (Lanczos / bicubic resampling)
Chất lượng
Lossless for PNG/WebP; JPEG quality 90 default (adjustable)
Speed
Resizing completes in under 2 seconds for most images
Security
HTTPS transfer · isolated temp dir · auto-purged in 2 h
Downscale algo
Lanczos (sharpest)
Upscale algo
Bicubic interpolation
Ratio lock
One dimension auto-calculates
Hướng dẫn đầy đủ
Image Resizing Guide: Pixels, Aspect Ratios & Social Media Sizes
Resizing images correctly is a fundamental skill for web developers, designers, and content creators alike. Getting dimensions wrong can break layouts, slow pages, or produce blurry visuals. This guide covers everything from resampling algorithms to social media presets.
Understanding Pixel Dimensions vs Physical Size
Lanczos vs Bicubic: Which Resampling Is Best?
Lanczos resampling samples a wider neighbourhood of pixels and applies a sinc-based filter, preserving edge sharpness better than bicubic when reducing image size. It is the gold standard for downscaling photographs. Bicubic uses a 4×4 pixel grid and is faster — suitable for upscaling where you want smooth results. Nearest-neighbour (not used here) simply duplicates pixels and is only suitable for pixel art.
Aspect Ratio Lock and Why It Matters
An aspect ratio is the proportional relationship between width and height (e.g. 16:9, 4:3, 1:1). Resizing without locking the ratio stretches or squishes the image. The aspect ratio lock calculates the missing dimension automatically: if your original is 1600×900 and you enter a width of 800, the height becomes 450 — maintaining the 16:9 ratio perfectly.
Social Media Image Size Cheatsheet
Quick reference for common platforms: Instagram — feed post 1080×1080 (square), story 1080×1920, landscape 1080×566. Twitter/X — post image 1200×675, header 1500×500, profile 400×400. Facebook — cover 820×312, shared image 1200×630. LinkedIn — post image 1200×627, banner 1584×396. YouTube — thumbnail 1280×720.
When to Use Percentage Scaling Instead of Fixed Pixels
Percentage scaling is useful when you want to reduce all images by the same relative amount without knowing exact output dimensions. Scale to 50% for quick thumbnail generation, or 75% to cut file size while preserving proportions. It is particularly handy for batch operations where every input image has different dimensions but you want each output halved.