What is a “diffusion model”?

[Last Updated: 11/21/2025]

Overview (TL;DR)

Midjourney is a diffusion model, which means it starts with random visual noise (a seed) and gradually denoises it into an image by following the visual patterns it learned from millions of captioned images. It doesn’t think or make decisions— it simply transforms noise toward the shapes, textures, and styles your prompt describes.

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Wait, before I read this, why do I even care that Midjourney is a diffusion model?

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Knowing that Midjourney is a diffusion model gives you the right instincts for prompting.

Understanding diffusion helps you understand why the prompt guidelines exist, not because you need technical knowledge, but because the guidelines map directly to diffusion strengths and weaknesses.

Ok, Midjourney is a diffusion model? What’s that?

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A diffusion model doesn’t think, decide, or imagine the way a human does, or even the way other familiar AIs do, like Claude, or Gemini, or ChatGPT. You can talk to those AIs like they’re people. You can’t talk to Midjourney that way unless you’re in a special 🐇Conversational Mode.

A diffusion model like Midjourney uses a mathematical process to transform random visual noise into a finished image. The key idea is simple:

It learns what things tend to look like by studying millions of examples.

Let’s walk through that in everyday terms.

1. Learning Patterns (Not Rules or Logic)

During training, Midjourney’s model is shown millions of images paired with text:

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