ImageNet is a database of over 15 million hand-labeled, high-resolution images in roughly 22,000 categories. This database is organized just like the WordNet hierarchy, where each concept is also called a synset (that is, synonym set). Each synset is a node in the ImageNet hierarchy. Each node has more than 500 images. 

The ImageNet Large Scale Visual Recognition Challenge (ILSVRC) was founded in 2010 to improve state-of-the-art technology for object detection and image classification on a large scale:

Following this overview of ImageNet, we will now take a look at various CNN model architectures.