Convolutional neural networks (CNNs) are a type of neural network designed to process images. CNNs use a series of convolution and pooling layers to extract features from images. Convolution multiplies the image with filters to produce feature maps, while pooling reduces the size of the representation to reduce computation. This process allows the network to learn increasingly complex features from the input image and classify it. CNNs have applications in areas like facial recognition, document analysis, and image classification.