Hi! I think this is what I was referring to in the other thread:
If you just want to label images, you don't need to add them to a dataset first. Datasets are where Prodigy saves annotations. If you just want to label images, all you need to do is pass the image.manual recipe the path to your images directory, and Prodigy will take care of the rest:
prodigy image.manual your_dataset /path/to/images --label DOG,CAT
As you label the images, they'll then be saved to the dataset your_dataset. (The error you saw is happening because you're not providing it with an input source – just a dataset to save the annotations to.)