Image Size Converter

About This Tool

Purpose & User Intent: This tool addresses the need to convert image dimensions across display and print units while optionally accounting for DPI. Intended users include graphic designers, front-end engineers, asset managers, and production studios who size images for multiple media channels. When assets must align with specific output sizes or density, accurate unit conversion prevents under- or over-sized assets. The tool supports common units (pixels, inches, centimeters, millimeters, points) and provides DPI-aware calculations to translate between physical and digital dimensions. Use cases include preparing social media images with fixed pixel widths, exporting print-ready images at 300 DPI, and validating asset specs across teams. Core value lies in precision, speed, and reproducibility: a single source of truth for dimension data that reduces manual calculation errors and aligns with project briefs. The engine can handle single-value conversions and batch scenarios, enabling quick checks for numerous assets. Distinctive features include explicit DPI handling, batch-ready input parsing, and a clear separation of unit domains to avoid ambiguities between screen-based and print measurements. Edge cases such as non-numeric values, unsupported units, and missing DPI values are addressed with strict validation rules, returning explicit, unambiguous results. Core Logic & Features: The tool implements a two-tier conversion approach: (1) unit normalization (px, inches, cm, mm, pt) and (2) DPI-aware mapping between display and print sizes. Required features include: input validation, unit mapping, DPI handling, ability to convert between any two units, and a small batch mode. Optional/advanced features: auto-detection of DPI from metadata, batch CSV/TSV input, and export options (JSON/CSV). Inputs & Outputs: Inputs include value (number), source_unit (enum), target_unit (enum), dpi (number, optional, default 72). Sample: value=1200, source_unit=px, target_unit=in, dpi=96. Outputs include converted_value (number) and units; If applicable, physical_size values in inches/cm/mm; Output formatting uses decimal with up to 4 decimals, trimmed trailing zeros. Algorithms & Calculations: Core formulas: inches = px / dpi; cm = inches * 2.54; mm = cm * 10; pt = inches * 72; If converting from physical units to pixels, px = (value_in_inches * dpi); Then apply conversion to target unit. The tool uses consistent rounding to 4 decimals; references: standard unit conversion tables. Error & Edge Cases: Invalid numeric input yields error flag; Unsupported unit yields clear error; Missing dpi defaults to 72; DPI <= 0 invalid; high-precision values supported. Industry/Region & Localization: Supports metric and imperial units; DPI values align with printing (300 DPI), screen (72/96/120/144) families; no currency or region-specific formats; number formatting uses dot as decimal separator. Assumptions & Exclusions: Assumes inputs numeric; Not performing image resampling, color space changes, metadata extraction; Not resizing actual image; Not handling aspect ratio.

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