Where the prompt hides in a JPEG
Automatic1111, Forge and SD.Next store the same parameters string as the PNG version, but inside the EXIF UserComment tag (0x9286), encoded as UTF-16 with a UNICODE prefix. Some tools use ImageDescription, XPComment or an XMP packet instead. PNGMeta walks the JPEG APP1 segments, parses the TIFF structure, decodes UserComment/XP tags and shows the parameters split into prompt, negative prompt and settings.
WebP
WebP stores EXIF and XMP in RIFF chunks (EXIF, XMP ). PNGMeta reads both. Note that WebP produced by social platforms or CDNs is almost always stripped.
JPEG that came from a PNG
If someone converted a PNG to JPEG with a generic editor, the PNG text chunks were dropped and nothing was written into EXIF — the prompt is gone. Only images saved as JPEG by the generator keep it. See why images lose metadata.
Frequently asked questions
Can a JPEG contain a Stable Diffusion prompt?
Yes. When Automatic1111/Forge save JPEG or WebP, the parameters go into EXIF UserComment. Upload the file to pngmeta.app to read them.
Why does my JPEG show EXIF but no prompt?
The EXIF may only contain camera/software fields. If UserComment, ImageDescription and XMP are empty, the file was not saved by an AI tool that embeds prompts, or was re-encoded afterwards.