AddMetaData (Mikey)

Add Metadata does one narrow, genuinely useful thing: it lets you attach a custom key/value pair to an image so it gets written into the file when you save it - beyond whatever ComfyUI already embeds by default. The README gives credit to a community member (masslevel) for the idea, and it's a good one: if you're testing multiple checkpoints, LoRA combinations, or prompt variants, this is how you make sure the exact detail you care about actually ends up traveling with the file, instead of living only in your memory or a spreadsheet somewhere.

The mechanism is straightforward - you pass an image through the node along with a label (the metadata key) and a text_value (the value), and it returns the same image with that pair attached, ready to continue down your graph. The metadata doesn't actually land in a file until a Save Image node downstream writes it into the PNG - this node stamps the data, the save node is what commits it to disk. If nothing downstream saves the image with metadata support, the stamp doesn't go anywhere.

The inputs that matter: label is a single-line string - keep it short and identifying, like "checkpoint" or "lora_stack". text_value is multiline, so it can hold something longer, like a full list of LoRAs and weights used. Both can be converted to node inputs (right-click → convert to input) if you want to pipe in dynamic values instead of typing them - for example, feeding a CheckpointHash output straight in as the value, or a TextConcat result that's already built a summary string for you. The output is IMAGE, meaning you chain multiple Add Metadata nodes back to back if you want to stamp more than one key - one node per key/value pair.

Installing it

Comes with the full Mikey Nodes pack. Through ComfyUI Manager, search "Mikey Nodes." Manually:

cd ComfyUI/custom_nodes
git clone https://github.com/bash-j/mikey_nodes

Restart ComfyUI. No models or extra dependencies for this node - it's metadata bookkeeping, not image generation.

Common issues

The most common way this "doesn't work" is actually a chain issue, not a node issue: if you're saving to a format that doesn't carry the same PNG-text metadata channel (JPEG and WEBP are the usual culprits), the label/value you stamped won't survive the save - PNG is the safe choice if this data matters to you. Beyond that, stacking a lot of Add Metadata nodes to record everything about a run is fine functionally, but it does bloat the embedded text in the resulting file - worth being selective about what's actually worth recording versus what you can regenerate from the workflow JSON that most Save Image nodes already embed by default anyway.