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Helvety Image Upscaler
Web AppApr 28, 2026Art by Alexandre Calame
Browser-based image upscaler with on-device AI (Real-ESRGAN via WebGPU/WASM) and a canvas-resample fallback: 2×/4× batches, target width or height with locked aspect ratio, and limits so tabs stay responsive.
About
Helvety Image Upscaler runs a Real-ESRGAN ONNX model inside a Web Worker via onnxruntime-web (WebGPU with WASM fallback) so PNG, JPEG, and WebP images can be upscaled entirely on-device. The model downloads lazily on first AI run and caches locally; a high-quality canvas-resample fallback is used automatically when WebAssembly is unavailable. No Helvety-hosted image conversion in the normal flow, and very large exports may be clamped to fit each browser’s canvas limits.
Access model
Launch the tool without signing in. Usage stays free; automated safeguards keep abusive floods from degrading shared infrastructure.
Operator knobs
- Use the built-in Real-ESRGAN AI engine by default, with canvas resampling only as an automatic fallback for browsers that cannot run WebAssembly.
- Pick a fixed multiplier (2×, 4×) or clamp to a target width or height.
- Batch up to five files per run, downloading individually or all together once ready.
- Mind the in-app caps: 32 MP for the canvas fallback, 4 MP per image for AI upscaling (Float32 stitching buffers fit comfortably in a worker).
Why it fits sensitive screenshots
Frames never leave your session in the supported pipeline, including the AI flow, which makes it easier to audit your own asset workflow when polishing marketing shots or reference stills.
Access
Current Helvety products in this catalog are free to use with no paid tiers or subscriptions.
Features
- On-device AI super-resolution (Real-ESRGAN via onnxruntime-web)
- WebGPU acceleration with automatic WASM fallback
- Lazy model download cached locally (works offline after first run)
- Tiled inference with linear-blend stitching for seam-free output
- Automatic canvas-resample fallback for browsers without WebAssembly
- 2× and 4× scale presets
- Target width/height mode with preserved aspect ratio
- Batch processing (up to 5 images)
- No login or account required
- Dark & light mode support