Midjourney Blend (Image Mix)

Midjourney Blend (Image Mix) does what MJ's Discord /blend does - take two images, mix them into a new one - but instead of dragging files into a chat, you wire two IMAGE tensors into a node. It's the pack's most self-contained node: no prompt required, no grid to interpret, just two images and a settings panel, and out comes a hybrid plus a fresh task_id you can keep acting on.

How it works

The node converts both input tensors to base64 PNGs, posts them to /mj/submit/blend with a botType and a dimensions string, gets a task_id back, and then polls the same fetch endpoint as every other MJ node in this pack until the blend is done. Two details worth knowing:

• Dimensions aren't "1:1" like everywhere else - the API speaks SQUARE (1:1), PORTRAIT (2:3), or LANDSCAPE (3:2).
• The seed is actually a cache-buster. Midjourney's relay caches identical requests and will happily hand you the same result for the same inputs. When seed is -1 the node uses a millisecond timestamp as the request's state, so every blend is treated as a fresh job. If you want a reproducible blend, pass a real seed - but know that identical inputs with the same seed can return the cached image.

Inputs and outputs

• image1, image2 - required IMAGE tensors. Both get converted to PNG and sent up.
• dimensions - SQUARE (default), PORTRAIT, LANDSCAPE.
• bot_type - MID_JOURNEY or NIJI_JOURNEY (the anime model).
• quality - a free-form string; the API doc suggests "hd" or leave it empty.
• seed - -1 for fresh (default), or a fixed value up to 2^31−1.

Outputs: image (the blend), task_id (STRING), and buttons (DICT of MJ actions). Wire task_id into the Upscale/Variation nodes to refine the blend further - that's the natural next step, since a blend is itself a 2×2 grid.

Installing

Via ComfyUI Manager (search "ComfyUI-MidjourneyHub") or:

cd ComfyUI/custom_nodes
git clone https://github.com/jiaqianjing/ComfyUI-MidjourneyHub
# restart ComfyUI

Put your own key and URL in config.ini under [MIDJOURNEY_API] - the repo ships with the author's keys committed, so replace them before spending a single credit. Dependencies are the pack's usual light set (aiohttp, openai, nest_asyncio); nothing heavy.

Where people get burned

The same relay caveats as the rest of the pack apply (unofficial MJ API, Chinese-language console, api_url subject to change without notice - check it first when jobs fail). One blend-specific gotcha: if you're feeding it images from other ComfyUI nodes, make sure they're actual RGB images and not masks or latent-shaped tensors - the base64 conversion will happily mangle a wrong-shaped input into a corrupt PNG that the relay rejects.