IMAGE Preview in Background @ vrch.ai

Sometimes you don't want a tidy little preview pane. You want the image filling the screen, wallpapered behind everything, the way a projectionist or a VJ thinks about output. The IMAGE Preview in Background node does exactly that: it pops a window that shows your incoming images as a fullscreen-style background, and it's the current, non-legacy version of the pack's preview-in-background idea.

What it is

The mechanism is a pure display sink. Feed it images and it renders them in a popped-up window, sized to display_option - your pick of original, fit, stretch, or crop. That option is the one setting you'll fiddle with most: fit letterboxes the image inside the window, stretch warps it to fill every pixel (great for a projected look, terrible for anything with text), crop fills the frame and cuts the edges, and original shows it at native size. background_display (default on) is the master toggle that actually shows the background - leave it off and the node goes quiet.

The batch settings are what separate this from a plain preview. batch_display turns on cycling through a batch of images, and batch_display_interval_ms (default 200) sets how fast it flips between them. Combined, those two make it a quick-and-dirty slideshow against your desktop - a good way to eyeball an entire batch of generations without tabbing through a gallery, and a natural fit for the kind of live iteration this pack encourages. There are no outputs and it's a terminal node by design; it's a preview, not a processing step, so whatever you feed it just gets shown.

How to install

Install is the shared pack story, unchanged:

cd ComfyUI/custom_nodes
git clone https://github.com/VrchStudio/comfyui-web-viewer
cd comfyui-web-viewer
pip install -r requirements.txt

restart ComfyUI. Manager users search "ComfyUI Web Viewer". Windows portable: python_embeded\python.exe -m pip install -r ComfyUI\custom_nodes\comfyui-web-viewer\requirements.txt. No models to fetch.

Common issues

The honest comparison: the legacy sibling (IMAGE Preview in Background (Legacy)) does the same core job but routes through the pack's channel system with a channel field and a refresh_interval_ms. If you're starting fresh, use this new node - it's the leaner, channel-free version, and it'll be the one that keeps getting maintained. The one real gotcha is the popup-window behavior: like all the viewer nodes in this pack, the preview window comes from the browser, so if you're on Chrome and serving over a LAN you may need the README's insecure-origin flag trick to let the popup load. Once it's up, you've basically got a one-click fullscreen output for whatever your graph is generating.