Provides nodes geared towards using GIMP as a frontend for ComfyUI. Modified from https://github.com/Acly/comfyui-tooling-nodes, thank you Acly.
What changed: Load Image, Load Mask, and Send Image were modified to send, receive, and process base64 encoded RGBA data rather than base64 encoded PNG data.
Sending and receiving images
Installation

Sending and receiving images

Load Image (GIMP)

Loads an image from an RGBA image embedded into the prompt as base64 string.

Inputs: base64 encoded binary data of an RGBA image
Outputs: image (RGB) and mask (alpha) if present

Load Mask (GIMP)

Loads a mask (single channel) from an RGBA image embedded into the prompt as base64 string.

Inputs: base64 encoded binary data of an RGBA image
Outputs: the first channel of the image as mask

Send Image GIMP (WebSocket)

Sends an output image over the client WebSocket connection as RGBA data.

Inputs: the image (RGB or RGBA)

This will send one base64 encoded message for the image via WebSocket:

12<RGBA-data>

That is one 32-bit integer (big endian) with value 12 followed by the base64 encoded RGBA binary data. There is also a JSON message afterwards:

{'type': 'executed', 'data': {'node': '<node ID>', 'output': {'images': [{'source': 'websocket', 'content-type': 'image/png', 'type': 'output'}, ...]}, 'prompt_id': '<prompt ID>}}

You can see how the data is received in the GIMP plugin at https://github.com/nchenevey1/gimp-comfy-tools

Send Image with Dimensions GIMP (WebSocket)

Sends an output image over the client WebSocket connection as RGBA data.

Inputs: the image (RGB or RGBA)

This will send one base64 encoded message for the image via WebSocket:

14<width><height><RGBA-data>

That is one 32-bit integer (big endian) with value 14 followed by the base64 encoded Width (32 bit), Height (32 bit), and RGBA binary data. There is also a JSON message afterwards:

{'type': 'executed', 'data': {'node': '<node ID>', 'output': {'images': [{'source': 'websocket', 'content-type': 'image/png', 'type': 'output'}, ...]}, 'prompt_id': '<prompt ID>}}

You can see how the data is received in the GIMP plugin at https://github.com/nchenevey1/gimp-comfy-tools

Installation

Download the repository and unpack into the custom_nodes folder in the ComfyUI installation directory.

Or clone via GIT, starting from ComfyUI installation directory:

cd custom_nodes
git clone https://github.com/nchenevey1/comfyui-gimp-nodes.git

Restart ComfyUI and the nodes are functional.