📥🖼 Load Image Base64 (Transparency)

Most "load image" nodes in ComfyUI assume the image is a file sitting on disk somewhere you can point a file picker at. This one assumes the opposite: the image already exists as a base64-encoded string, probably because something called the ComfyUI API programmatically and passed the image data inline in the request body instead of uploading a file to input/ first. If you're building a workflow meant to be driven by an external script or app rather than clicked through in the browser, this is the entry point that fits that shape.

How it works

It takes a base64 string and decodes it straight into ComfyUI's internal image tensor, alpha channel included - so unlike ComfyUI's stock image-loading nodes, transparency in your source data survives the trip. It's flagged as an output node in its schema, which in ComfyUI terms means it can also act as a terminal display step in the graph, not purely a pass-through loader feeding something downstream.

Inputs and outputs

Just one required input: base64_data, a STRING field with no default value - you either paste a base64 string in manually for testing, or wire it from whatever upstream source is producing one (an API-triggered workflow parameter, typically). Two outputs: IMAGE, and MASK - the alpha channel extracted separately, exactly like the pack's other transparency-aware loaders, so you can wire the mask straight into anything expecting a matte (cutting the subject out, compositing, inpainting the background, and so on).

Installing it

It ships with the rest of Bjornulf_custom_nodes - ComfyUI Manager, search the pack title, or cd ComfyUI/custom_nodes && git clone https://github.com/justUmen/Bjornulf_custom_nodes, then restart. No extra dependency specific to this node.

Common issues & troubleshooting

Worth knowing going in: this node isn't documented individually in the pack's README, which walks through roughly 170 other nodes with descriptions and screenshots. The closest thing in the README's own node index is an entry called "Load from Base64," still marked "Coming soon" as of the current documentation - this node looks like it may already be the real, shipped version of that idea, just ahead of the docs. That's consistent with how this pack operates generally (the README's own banner warns "very active development, work in progress"), but it does mean you're working from the schema rather than a walkthrough - treat the inputs/outputs above as authoritative over anything you might find searching for a "Load from Base64" writeup.

Practically: if the node errors immediately, check that base64_data is actually a valid base64-encoded image string and not, say, a data URI with the data:image/png;base64, prefix still attached - depending on how strict the decoder is, that prefix can trip up a raw base64 parser. Strip it down to just the encoded payload if you're pasting from a browser dev tools panel or an API response that includes the full data URI.