FilenamePrefix By Date

By default, Save Image stamps your work ComfyUI_00001.png and counts up. Fine for five images, useless after five hundred, and the name tells you nothing about what's inside. "FilenamePrefix By Date" generates the filename_prefix string from the current clock, so each run lands in a per-day folder with a minute-level timestamp: 20260826/20260826_1437.png. You can always find last Tuesday's renders, and you never guess at contents from a filename again.

The mechanism is short and worth reading once. The node grabs datetime.now(), formats it two ways - %Y%m%d and %Y%m%d_%H%M - and with the date-folder toggle on, joins them with os.path.join. That last bit is why the README talks about path delimiters: on Linux and Mac you get forward slashes, on Windows backslashes. Then an optional _seed and an optional _suffix get appended, in that order.

One subtlety straight from the source: the author marks the node IS_CHANGED, and in practice ComfyUI re-evaluates it every queue - the stamp is taken when the node runs, not when you queued. The marker is set the slightly-wrong way (a plain True instead of the NaN idiom ComfyUI's docs recommend), and as a side effect you may see the console log a harmless warning line about a "bool" object not being callable each time it fires. That's normal, and it's also why each job in a batch gets its own minute - the node genuinely re-runs.

Inputs, and there are only three:

• seed (INT socket) - optional. Wire your KSampler's seed here and it lands in the name: 20260826/20260826_1437_1234567890.png. This is the one input that earns its keep, because it makes filenames unique even when two runs land in the same minute.
• suffix (text) - a short label like 2x or test, appended after the seed.
• enable_date_folder (toggle, default on) - off collapses everything to flat names: 20260826_1437.png, no folder.

The single output is a STRING, filename_prefix. Wire it into Save Image's filename_prefix input - right-click that widget and "Convert to input", or read the value and type it in. Save Image treats / in a prefix as a folder separator, which is exactly why the date-folder mode creates real directories for you.

Gotchas, briefly. Minute resolution means two images in the same minute with the same seed and suffix share a name and the second silently overwrites the first - that's precisely why the seed input exists, so wire it if you queue batches. The timestamp reflects when the node executed, so a job that sat in the queue for an hour gets the hour-later stamp, which is honestly what you want for file organization anyway.

Install is the pack install: ComfyUI Manager, search "ardent", install, restart - or cd ComfyUI/custom_nodes && git clone https://github.com/ardentillumina/ardent-comfy and restart. The whole pack is three tiny utility nodes with no dependencies and no models to download, and this is the one you'll actually use. Not glamorous, but once you have a dated, searchable output folder, ComfyUI_00001 starts to feel genuinely primitive.