How Stable Diffusion marks images
Automatic1111 and related Stable Diffusion web interfaces store generation parameters in PNG `parameters` tEXt and zTXt chunks.
What gets embedded in the file
Positive prompt, negative prompt, steps, sampler name, CFG scale, seed, model checkpoint hash, and LoRA references.
Lossless cleaning methodology
Directly filters out `parameters` and ancillary text chunks while copying IDAT image data bit-for-bit.
Technical boundaries and compliance
Pure metadata removal. Pixel data is completely unchanged.