ZML_桥接预览图像

A normal preview node shows you the latest image and forgets it the moment the next run happens. ZML_ImageMemory (ZML_桥接预览图像, "bridge preview image") is the one that remembers - it holds your last several runs in a queue, shows them all in the node, and lets you flip back through them or output a specific one. If you've ever stared at one good result and thought "wait, which seed was the previous one?", this node is aimed at you.

It's from ComfyUI-ZML-Image, zml-w's 160+ node pack, and it's a deliberate riff on the bridge preview concept from the Impact Pack (the README credits it as inspiration). It lives in the pack's tools subcategory.

How it works

Every image that flows in gets cached per-node-instance and pushed onto a queue. The 暂存次数 (cache count) knob sets the queue length (1–10): set it to 3 and the node keeps the last three runs' images, displays them together, and can output any of them. Because the cache lives in the backend keyed to the node's unique ID, the images survive between runs - that's the whole trick, and it's why it's called "memory."

Three controls do the interesting work:

• 选择输出索引 (output index) - 0 outputs everything cached (same-resolution images merge into one batch; different resolutions come out as a list). 1–50 picks a single image by index, counting each individual image - a batch of 5 counts as 5 separate indexed images. Out of range just returns the last one.
• 关闭输入 (disable input) - stop executing the upstream nodes entirely, locking the node to its current cached state. This is lazy evaluation in practice: toggle it on and your sampler stops running while you compare what's already stored.
• 关闭输出 (disable output) - let it receive new images but stop downstream nodes from executing.

The output is a 图像 list (the node is also an output/preview node, so the cached images render right in the node body).

What it's actually for

Comparing generations. Run three seeds, set 暂存次数 to 3, and instead of scrolling your output folder you flip through all three in the node. Use 关闭输入 to freeze the graph while you compare, then pick the winner by index and feed it onward. It slots naturally into the "review then decide" workflow the pack builds toward - the README describes it as the hub for pausing and choosing outputs.

Installing it

Same pack install as everything else:

cd ComfyUI/custom_nodes
git clone https://github.com/zml-w/ComfyUI-ZML-Image

restart, or install via ComfyUI Manager (search "ComfyUI-ZML-Image"). No extra models; the heavy requirements (OpenCV, scipy, ultralytics) belong to the pack's other nodes.

Where people get caught

The cache is keyed to the node instance in the workflow - duplicate the node and you get a separate cache, not a shared one. And if a run fails, the cached images from before are still there, which is great - until you forget they're stale and hand a downstream node an old image thinking it's fresh. The 关闭输入/关闭输出 toggles are your guardrails there. It's a review tool, so treat it as the thing that shows you what you made recently, not as the current truth of your pipeline.