💾🖼 Save Image (tmp_api.png) ⚠️💣

The node's own display name carries a bomb emoji, and that's the author warning you rather than decorating. This node saves whatever image you feed it to a single fixed path - output/tmp_api.png - every single time, no numbering, no folder. Run your workflow again and it overwrites the previous file. That's the entire feature: a scratch slot for "whatever the last generated image was," useful when something external is polling for the latest output, useless if you actually want to keep your generations.

How it works

There's nothing to configure - feed it an image and it writes it to that one fixed location, clobbering whatever was there. The use case this fits is an API-style handoff: something outside ComfyUI (a script, another app) checks tmp_api.png for the newest result rather than tracking filenames or watching a folder for new files. It's the same "last output at a fixed path" idea the pack uses elsewhere - Save image for Bjornulf LobeChat maintains a similar always-latest symlink for its own integration - just simpler here, with no companion app assumed.

The inputs and outputs that matter

• image (IMAGE) - the only input, and the only thing this node does anything with.
• No outputs. It's a dead end in the graph: the image goes in, the file gets written, nothing comes back out to wire further downstream.

How to install it

Via ComfyUI Manager: search Bjornulf_custom_nodes, install, restart. Manually:

cd ComfyUI/custom_nodes
git clone https://github.com/justUmen/Bjornulf_custom_nodes
cd Bjornulf_custom_nodes && pip install -r requirements.txt

then restart ComfyUI. Nothing this node needs beyond basic file writing, but you're installing the full 170-node pack and its shared requirements.txt regardless.

Common issues & troubleshooting

You lost a generation you wanted to keep. This is the single most predictable failure mode - run the workflow twice and the first image is just gone, overwritten by the second. If you want to keep every output, use the pack's Save Image to a Folder node (or core ComfyUI's Save Image) instead; this node is deliberately not that.

Something else is reading the file mid-write. If an external process is polling tmp_api.png on a tight loop, there's a real chance it reads a partially-written or stale file right as this node overwrites it. Add a small delay or a completion signal on the reading side rather than assuming the write is instantaneous.

Confusing it with a persistent save. The name says "tmp" and the title carries the warning icons for a reason - treat this strictly as a short-lived handoff slot, not an archive, and you won't be surprised by it.