Moss Image 图像生成/编辑

Moss Image is the smallest node in ComfyUI_Seedance: a prompt box, an aspect-ratio dropdown, and one optional reference image. That's it. There's no sampler, no steps, no CFG, no batch count, no negative prompt. If you came here hoping to tune something, you're going to be disappointed - and if you came here because you want an image out of a graph in about twenty seconds with zero VRAM, it'll do exactly that.

The important thing to understand before you run it: this node does not generate anything on your machine. It's an HTTP client. Your prompt goes to api.seedance.nz, a paid reseller gateway, moss-image does the work on someone else's GPU, and the result comes back as a normal ComfyUI IMAGE tensor that wires into your graph like a local sampler's output. That's the whole category of API-wrapper nodes (external-api-nodes.md), and it's the honest way to read this pack: T8mars runs 贞贞的平价AI小屋, publishes on the Comfy Registry as t8star under node id seedance, and every node in it is a front-end to that one metered API.

What it actually sends

The node is deliberately thin on the wire. The payload contains exactly four things: the model name moss-image, your prompt, metadata.ratio, and - only if you connected one - a single uploaded reference URL. No resolution, no n, no batch, no API-side seed. The author's changelog says so, the source agrees, and during the v0.22.0 smoke test both the text-to-image and the reference-edit call came back at 1456×1456.

So the size is the server's call, not yours. Pick a ratio and live with the pixels.

The inputs you'll actually touch

prompt is required and it's a real validation, not a hint - a blank string fails before anything is submitted, so a fat-fingered prompt costs you nothing.

ratio gives you eight fixed options: 1:1, 2:3, 3:2, 3:4, 4:3, 9:16, 16:9, 21:9. Note the default is 9:16, which is a portrait-first choice a lot of people won't expect. If your first test image comes out tall when you wanted square, that's why.

image1 is the optional single reference. Connect it and you're in edit mode; leave it unconnected and you're in text-to-image. One image, and strictly one - if you feed it a batch the node rejects you with "Moss only supports a single reference image, not a batch." So don't pipe a Repeat Image Batch or a multi-load straight in.

There's also skip_error, which returns a placeholder error image instead of killing the workflow, and a seed. That seed is worth understanding: the pack injects a standard ComfyUI seed/cache control into every generation node, then strips it back out before the request goes out. It's a cache key, not a randomizer. Fix it and ComfyUI skips re-running the node instead of billing you for an identical image; change it and you get a new call. It will never reproduce a previous result.

Outputs

image is the one that matters - into Preview Image, Save Image, or straight into an upscaler. image_url is the temporary result link, task_id is the remote job id, and response is the full JSON if you need to debug what the API actually said. Result URLs expire; the node has already downloaded and decoded a local copy for image, but if you're archiving, save it properly.

Install

Manager is easiest - search ComfyUI Seedance or seedance in ComfyUI-Manager, or:

comfy node install seedance

Manual, if you prefer to see the code first:

cd ComfyUI/custom_nodes
git clone https://github.com/T8mars/ComfyUI_Seedance.git
cd .. && python -m pip install -r custom_nodes/ComfyUI_Seedance/requirements.txt

That requirements file is one line - requests>=2.28. No model downloads, no torch version roulette, no 20 GB of weights. Restart ComfyUI and the node is under the Seedance category.

Then give it a key: add a Seedance API Config node and wire its api_config output in, set SEEDANCE_API_KEY before launching, or drop it into custom_nodes/ComfyUI_Seedance/config/.env. Forgetting this is the number one first-run error - you get a complaint about a missing key, not a bad image.

Where people get burned

The failure modes here are boring, which is a compliment. A batch into image1, a blank prompt, a ratio that isn't in the eight-item list (which happens when you load a workflow saved against a different node version), and TLS trouble on corporate networks - for that last one the README says update requests/certifi first, then reach for SEEDANCE_CA_BUNDLE. If you want thirty variations, don't loop this node. The pack ships SeedanceConcurrent_Moss_Image_Submit with a 30-slot receiver, and hammering one node serially is the slow way to spend the same money.

One last thing, because it's the honest read: moss-image is a closed model behind a reseller, so there's no local fallback and no community lore to check it against - it barely registers on r/comfyui at all. Treat your first few images as a test of whether the price/quality trade suits you, not as a solved recipe.