Pixel-Level Visual Diff Tool

Professional pixel-level image analysis powered by WebAssembly algorithms. Features PSNR calculations, euclidean distance comparison, and thermal difference heatmaps for precise design verification and quality assurance.

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First Image

Upload First Image

JPG, PNG, WebP • Max 10MB

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Second Image

Upload Second Image

JPG, PNG, WebP • Max 10MB

Complete Privacy Protection

All image processing happens locally in your browser. Your images never leave your device, ensuring complete privacy and security for your visual assets.

Complete Privacy Protection

All processing happens locally in your browser. Your photos never leave your device, ensuring complete security for confidential design work and sensitive visual assets.

How It Works

Upload Photos

Select two photos you want to analyze side-by-side

Pixel-Level Analysis

Execute WebAssembly-powered algorithms for precise pixel comparison and thermal heatmap generation

Advanced Metrics

Review PSNR scores, similarity percentages, and euclidean distance calculations

Advanced Algorithm Features

Interactive Slider

Drag the slider to instantly reveal differences between photos with smooth transitions

Metadata Inspection

Analyze file properties, dimensions, aspect ratios, and timestamps in a detailed table

Side-by-Side View

Clear visual analysis with synchronized photo positioning and hover effects

WebAssembly Algorithms

High-performance pixel comparison using RGBA euclidean distance calculations and adaptive threshold detection

Thermal Heatmaps

Generate visual difference heatmaps with intensity-based coloring and exportable PNG format

Privacy Protected

All processing happens locally - your photos never leave your device

Core Analysis Algorithms

Euclidean Distance Calculation

Computes pixel-level differences using 4-channel RGBA euclidean distance:

√((R₁-R₂)² + (G₁-G₂)² + (B₁-B₂)² + (A₁-A₂)²)

PSNR Quality Metrics

Peak Signal-to-Noise Ratio calculation for image quality assessment:

PSNR = 20 × log₁₀(255 / √MSE)

Thermal Heatmap Generation

Creates intensity-based visual difference maps with adaptive coloring:

intensity = min(normalizedDiff × 2, 1)

Professional Use Cases

Design & Development Teams

•Verify design implementations match mockups
•Analyze before/after screenshots for UI changes
•Detect unintended visual regressions

QA & Testing Teams

•Automated visual regression testing
•Cross-browser rendering analysis
•A/B test visual verification

Common Analysis Scenarios

Design Verification

Analyze mockups against actual implementations to ensure pixel-perfect accuracy

Version Control

Track visual changes between different versions of your designs or screenshots

Quality Assurance

Detect rendering issues, layout shifts, or unintended visual changes

Frequently Asked Questions

How does the pixel-level analysis work?

Our WebAssembly engine performs euclidean distance calculations on every pixel's RGBA channels. The algorithm computes similarity percentages, PSNR scores, and generates thermal heatmaps to visualize differences with scientific precision.

What quality metrics are provided?

Beyond basic metadata, we calculate advanced metrics including similarity percentages, Peak Signal-to-Noise Ratio (PSNR), Mean Square Error (MSE), difference pixel counts, and processing time statistics for comprehensive quality assessment.

How are different image sizes handled?

Our algorithm automatically detects size mismatches and applies Lanczos3 resampling to align images for accurate pixel-level comparison. This ensures precise analysis regardless of resolution differences while maintaining image quality.

Is my data secure and private?

Absolutely! All photo processing happens entirely in your browser. Your photos are never uploaded to our servers, ensuring complete privacy and security for sensitive visual content.