WebUI Bridge Image Upscale

Upscaling is three different jobs wearing one name - adding pixels, inventing detail, or keeping video frames consistent - and they route completely differently. WebUI Bridge Image Upscale is squarely in the "adding pixels" camp: it takes an already-finished image and makes it bigger using a simple interpolation method, in pixel space, exactly as the pack's upscale settings specify. No model, no hallucinated detail, no rewriting of faces. Just larger.

So when do you want this node? When you've told the main Bridge node you want a 2x upscale and you want the image-space version of that, not the latent one. The pack's upscale module supports hires-fix, latent upscale, Ultimate SD Upscale and tile modes; this node is the concrete IMAGE step for the simpler end of that menu.

How it works

It reads the upscale section from module_config and looks for a scale_by value. It scales your image by that factor (default 2x, bounded to 0.01–8x) using ComfyUI's common_upscale. Which interpolation method does it use? The config's upscaler if that's one of ComfyUI's native methods (nearest-exact, bilinear, area, bicubic, lanczos) - otherwise it falls back to the node's fallback_method (default lanczos). So if the config names "4x-UltraSharp" or "RealESRGAN" - model upscalers that don't exist in this node - it quietly maps them to lanczos rather than pretending. That's the pack being honest: a real ESRGAN pass needs a model and belongs in a different node.

If the upscale module is disabled in the config, it passes the image through unchanged, which keeps the node harmless in workflows where you haven't configured upscaling yet.

Inputs and outputs

• image - the pixels to enlarge.
• module_config - the Bridge settings blob; scale_by and upscaler come from here.
• fallback_method - what to use when the configured upscaler isn't a native ComfyUI method. Lanczos is the sensible default.
• Outputs: image (the scaled result) and status (a string reporting the factor, method and new dimensions).

How to install

Part of the ComfyUI-WebUI-Prompt-Bridge pack: ComfyUI-Manager → ComfyUI WebUI Prompt Bridge, or clone into custom_nodes and restart. No models, no extra dependencies.

Common issues

The biggest misconception is expecting this node to add detail. It won't - interpolation can only resample what's there. If you want invented detail you need a generative path (a tile-ControlNet or an ESRGAN-family model), and this node is explicitly not that. Also worth knowing: it scales the image, so for a hires-fix you'd usually want the latent version (WebUI Bridge Latent Upscale) before the second sampler, then decode once. If you double up - latent upscale plus this pixel upscale - you're multiplying, and 2x twice is 4x of artifacts. Pick one path per pass.