Stable Cascade consists of three models: Stage A, Stage B and Stage C, representing a cascade for generating images, hence the name "Stable Cascade". Stage A & B are used to compress images, similarly to what the job of the VAE is in Stable Diffusion. However, as mentioned before, with this setup a much higher compression of images can be achieved. Furthermore, Stage C is responsible for generating the small 24 x 24 latents given a text prompt. The following picture shows this visually. Note that Stage A is a VAE and both Stage B & C are diffusion models.

For this release, we are providing two checkpoints for Stage C, two for Stage B and one for Stage A. Stage C comes with a 1 billion and 3.6 billion parameter version, but we highly recommend using the 3.6 billion version, as most work was put into its finetuning. The two versions for Stage B amount to 700 million and 1.5 billion parameters. Both achieve great results, however the 1.5 billion excels at reconstructing small and fine details. Therefore, you will achieve the best results if you use the larger variant of each. Lastly, Stage A contains 20 million parameters and is fixed due to its small size.