> ## Documentation Index > Fetch the complete documentation index at: https://openrouter.ai/docs/llms.txt > Use this file to discover all available pages before exploring further. # ImageGenerationRequestBackground Background treatment. `transparent` requires an output\_format that supports alpha (png or webp). ## Example Usage ```python theme={null} from openrouter.components import ImageGenerationRequestBackground # Open enum: unrecognized values are captured as UnrecognizedStr value: ImageGenerationRequestBackground = "auto" ``` ## Values This is an open enum. Unrecognized values will not fail type checks. * `"auto"` * `"transparent"` * `"opaque"`