Save Image Sequence (mtb)

When you're making video or animation, you often don't want a single PNG - you want a sequence of numbered frames in a folder, the kind you can hand to ffmpeg to assemble into a clip, or import into Blender, After Effects, or DaVinci as an image sequence. That's what this node writes. It's a thin wrapper around ComfyUI's normal save behavior, with the filename and folder formatting set up for sequential frames.

The mental model: a standard Save Image node dumps an output and mostly leaves naming to defaults. Save Image Sequence is built for the case where each frame needs a predictable, incrementing name (Sequence_0000.png, Sequence_0001.png, …) so a downstream tool can read them in order. If your endgame is a video file rather than stills, this is the save node that plays nicely with that pipeline.

How it works

It takes your image (or batch) and writes it out to the output folder using the prefix you set, with the frame number baked into the filename. The node's own words: it's "merely a wrapper around the save_images function with formatting for the output folder and filename," and "the current frame is used to determine which image to save." It's a terminal node - an output node with no downstream connections.

The inputs that matter

• images - the frame or batch to save.
• filename_prefix (default Sequence) - the base name each file gets, so your frames land as Sequence_####. Set this per project so different renders don't collide in the same folder.
• current_frame (default 0) - the frame index used in the filename. This is the key to the whole node: when you're generating one frame per run in an animation loop, you drive current_frame with your loop counter so each run writes the correctly-numbered file instead of overwriting frame 0 every time.

There are no outputs - it's the end of the line, it writes to disk.

How to install it

ComfyUI Manager: search MTB Nodes (comfy_mtb), install, restart. Or manually: cd ComfyUI/custom_nodes && git clone https://github.com/melMass/comfy_mtb and restart. Pure Python - nothing to download.

Common issues

The one that catches everyone: overwriting frame 0. If you leave current_frame at its default and run repeatedly, every run writes the same filename and clobbers the last one. In a per-frame animation setup you must feed current_frame a value that changes each run - your frame counter - or you'll finish with a single file instead of a sequence.

The second thing is knowing where the files actually go: into ComfyUI's output directory, under the folder implied by your prefix. If you can't find your frames, that's where to look. And when you go to assemble them, make sure the numbering is zero-padded and contiguous - a gap in the sequence (frame 5 missing) will make ffmpeg or your NLE either stop early or misread the frame order.