MiniMax H3 Save Image

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MiniMax H3 Save Image is the least glamorous node in the pack, and it's worth exactly one paragraph of "what it does" before the actually interesting bit about why it exists. It's the last node of a PreStage render: it takes the generated images, writes them under output/ as PNGs (default prefix minimax/stills/prestage), and reports them back to the stage card. Internal, dev-only, emitted automatically. You will not place it by hand.

The interesting bit is why the pack bothered to write it at all, when core's SaveImage would write the same file. The answer is a ComfyUI frontend quirk that's bitten enough people to be worth remembering. Core's SaveImage reports its result under the key "images", which is exactly what the stock frontend preview widget keys on. In an expanded graph, that widget would land on the canvas right under the PreStage card - which is already showing the same picture. Two previews of one still, stacked on top of each other, one of them a widget attached to a node that exists only for the duration of the render.

The pack's node sidesteps it by reporting under a key core doesn't know (mmc_image, in the same family as the video report key mmc_video). The report keeps its own path - the stage card reads it by name, exactly as it reads the video report - and the stray widget never appears. Same file on disk, same output folder, none of the UI noise.

The inputs that matter

• images - the rendered still, an IMAGE tensor.
• filename_prefix - default minimax/stills/prestage, so stills sort apart from finished renders in the gallery. Same folder the picker already looks at, which is the whole trick of the PreStage hand-off: a finished still is one chip away from being the next render's keyframe.

No outputs; it's an output node.

The workflow it serves

Put it in context and it makes sense. The PreStage generates stills for the H3 pipeline - a start frame, an end frame, a reference, a style sheet - with Krea 2, Ideogram 4.0, or H3 itself. The finished picture has to land where the Creator's @ picker can see it, and it has to report back to the stage card so the UI knows the render is done. This node is the delivery mechanism for both halves. The peer hand-off is by file, not by execution edge, so queueing a PreStage and its Creator together is deliberately not an ordering problem - and ComfyUI's input-hash caching makes an unchanged PreStage a cache hit on the render queue.

Installing

It ships with the pack - no separate install, and it's not a node you'd typically queue on its own. Install the pack however you install the rest:

cd ComfyUI/custom_nodes
git clone https://github.com/roadmaus/ComfyUI-MiniMax-Creator

Restart ComfyUI. No pip dependencies; you need a ComfyUI with comfy_extras/nodes_minimax_h3.py and whatever weights the PreStage's chosen architecture needs (Krea 2 / Ideogram 4.0 files, or the H3 set). If you never see this node on your canvas, that's the design working - but if you've ever wondered why a still you generated showed up twice in the UI, this is the answer.