What Does `unsqueeze` Do in PyTorch? (And Why Your Model Keeps Asking For It)

You passed a single image to your model and got ValueError: expected 4D input (got 3D input) . Someone on Stack Overflow said "just add . unsqueeze(0) " — and it worked.

Source: [Dev.to](https://dev.to/pytorchfromgroundup/what-does-unsqueeze-do-in-pytorch-and-why-your-model-keeps-asking-for-it-181a)