Right now, we can't provide any information about images output from ONNX models. This is in part due to our self-imposed limitation of not requiring the onnx module for the OnnxModel class. I also ran into complications and failure points when trying to get the required info from the graph, so this may be more complicated to attempt than I'd originally thought. May be possible to do it by limiting the set of usable ONNX models (i.e. how we eventually prevented NCNN models with scales less than 1 from loading).