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Binary Sizes

Current local release build sizes (as of the latest build):

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Baseline Build

File: dist/kimg_wasm_bg.wasm
  • Uncompressed: 934 KB
  • Gzipped: 346,582 bytes (~338 KB)
The baseline build targets maximum compatibility and runs on all WebAssembly-capable environments.

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SIMD Build

File: dist/kimg_wasm_simd_bg.wasm
  • Uncompressed: 1.1 MB
  • Gzipped: 385,388 bytes (~376 KB)
The SIMD build includes simd128 instructions for better performance on supported runtimes.

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Size Comparison

Build TypeUncompressedGzippedCompression Ratio
Baseline934 KB338 KB36.2%
SIMD1.1 MB376 KB34.2%
Difference+166 KB+38 KB
The SIMD build adds approximately 38 KB when gzipped, which is a reasonable trade-off for the performance benefits on supported platforms.

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Context and Comparison

kimg’s binary size is significantly smaller than alternatives:
  • kimg (baseline): 338 KB gzipped
  • kimg (SIMD): 376 KB gzipped
  • magick-wasm: 7 MB+ (mentioned in README as a comparison point)
For a full-featured image compositing engine with layers, blend modes, filters, and multi-format I/O, kimg’s binary size is optimized for web delivery.

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Size Optimization

The build process includes several optimizations:

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Release Profile

The Rust compiler uses release mode with optimizations:
  • LTO (Link-Time Optimization)
  • Code size optimizations
  • Dead code elimination

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wasm-opt

The build pipeline runs wasm-opt for additional size reduction:
  • Removes unused functions
  • Optimizes WASM instruction sequences
  • Reduces binary bloat

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Compression

When serving WASM files:
  • Always use gzip or brotli compression
  • Configure web servers with proper Content-Encoding headers
  • Gzip typically reduces size to ~35% of uncompressed
  • Brotli can achieve even better compression ratios

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Binary Size Variations

Binary sizes vary slightly based on:
  • Rust toolchain version - Newer compilers may produce different output
  • Optimization settings - Build profile configuration affects size
  • Feature flags - Enabled Cargo features change included code
  • Dependencies - Upstream crate updates can impact size
The sizes listed above represent typical builds and may differ by a few kilobytes in your environment.

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Loading Strategy

For optimal user experience:

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Progressive Enhancement

  1. Detect SIMD support in the runtime
  2. Load kimg_wasm_simd_bg.wasm if supported
  3. Fall back to kimg_wasm_bg.wasm for compatibility

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Lazy Loading

Load WASM only when needed: 
// Don't load at app startup
// Load when user initiates image editing
import { Composition } from '@iamkaf/kimg';
const doc = await Composition.create({ width: 128, height: 128 });

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Caching

Configure aggressive caching for WASM files: 
Cache-Control: public, max-age=31536000, immutable
WASM binaries are versioned with the package, so they can be cached indefinitely.

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Monitoring Size

Track binary size over time to detect regressions:
  1. Run ./scripts/build.sh
  2. Check dist/kimg_wasm_bg.wasm size
  3. Compare against previous builds
  4. Investigate significant increases
Consider adding size budgets to your CI pipeline to prevent unexpected binary bloat.

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