like train a classifier on so usually you have a data set and the data set has images and you put them through like a convolutional neural network and then you have to classify the image into one of I don't know how many classes on C for ten that's ten classes on image and it's a thousand and the data set is these images together with these labels now the idea of pre training is that you some where have a bigger data set that is sort of similar to the small data set but it's similar enough such that the network could learn something so what