Image Iterative Sampler

Deforum made a generation of SD users obsessed with the zoom-morph: take one image, re-sample it over and over with a little zoom, a little prompt drift, a little injected noise, and you get a hypnotic motion loop out of a still. That workflow has been awkward to port to ComfyUI for years because it's really a loop wearing a mask. Image Iterative Sampler is the loop wearing a node: point it at a latent, and it re-samples that image over and over - with progressive steps, exponential zoom, and fresh noise - until you have a batch of frames that animate like a deforum clip.

How it works

The sampler takes your starting latent and runs through cycles, each cycle holding a fixed seed and stepping through a ramp of denoise steps. Between iterations it applies the stuff that makes deforum look like deforum:

• Zoom - an exponential per-iteration multiplier (from the controller's zoom_rate, e.g. 1.05 = 5% per pass). The sampler does this in pixel space by decoding, scaling, and re-encoding through the VAE, because zooming raw latents corrupts them. That's why a VAE is mandatory when zoom is enabled.
• Noise injection - each pass gets noise_injection_strength worth of fresh noise so the image actually drifts instead of locking onto itself. Lock the injection seed (lock_injection_seed) to keep the drift pattern stable across cycles.
• Feedback - feedback_mode set to previous_iteration feeds the last output latent back as the next input, the classic chaining trick for smoother morphs.
• Optional wave extras - if you've threaded CLIP vision, style, ControlNet or IPAdapter data into the wave_config, each applies here per-cycle with wave-modulated strength.

Inputs that matter

• noise_injection_strength - the chaos dial. 0.1 is a gentle drift; 0.3+ gets actively trippy. This is the single knob that decides whether you get "smooth morph" or "glitch art."
• feedback_mode - none or previous_iteration. On for tighter continuity, off if you want each frame more independent.
• latent_image - your starting image, VAE-encoded.
• wave_config - from the Image Wave Controller; without it this node refuses to run (it requires a wave_config input).
• vae (optional) - required the moment zoom is on; also used for noise injection and checkpoint previews.
• checkpoint_config (optional) - from Iterative Checkpoint Controller, so long morphs save their progress.

Standard sampler dials round it out: model, positive, negative, seed, add_noise, sampler_name, scheduler, cfg (default 1.0). Output is a latent_batch - decode it and save the frames as a video or GIF.

Installing it

Ships in kentskooking-nodes: ComfyUI Manager → search kentskooking-nodes → install → restart, or:

cd ComfyUI/custom_nodes
git clone https://github.com/Kentskooking/kentskooking-nodes

Restart after. No models to download.

Common issues

• "ImageIterativeSampler requires a VAE input when zoom is enabled" - the most common stumble. zoom_rate ≠ 1.0 (or a nonzero zoom_max in the wave config) means the sampler needs a VAE for pixel-space zooming. Connect one, or disable zoom.
• Frames that drift into mush - noise injection too high or feedback_mode chaining runaway drift. Drop noise_injection_strength toward 0.05.
• It runs forever - exponential zoom multiplies frame resolution each pass; keep zoom_rate modest (1.01–1.05) unless you enjoy watching your VRAM evaporate.

The pack ships an example workflow (Image Iterative Sampler - zImage.json) - load that before you hand-roll anything.