iGPT is a GPT-style transformer trained without labels to predict the next pixel in low-resolution images. By modeling image structure rather than class labels, it learns representations that support later supervised classification. section 8.3
A surprising classification result
On CIFAR-10, iGPT reaches 96.3%, exceeding ResNet-152 despite never being trained to classify images. Its strongest classification features appear in the middle layers; accuracy falls by about 2.4% at the final layer. section 8.3
The result illustrates three linked ideas:
- Next-pixel prediction connects compression, prediction, and model inference. section 8.3
- Modeling P(X) preserves semantic structure alongside low-level visual detail, unlike objectives focused directly on P(Y|X). section 8.3
