title: Prediction on image with different size
body: <p>Is is possible to run prediction on images with different sizes than the training data? I have trained a unet_learner on pictures of a certain size (1000*1000) and exported it for later use. </p>
  
  <p>I then load it with the following: </p>
  
  <pre><code>learn = load_learner(modelpath)
  preds = learn.predict(image) 
  </code></pre>
  
  <p>But what happens if the size of the input image is different? </p>