The MNIST database of handwritten digits has a training set of 60,000 examples, and a test set of 10,000 examples.
The digits have been size-normalized and centered in a fixed-size 28x28 image.
The CIFAR-10 dataset consists of 60000 32x32 colour images in 10 classes, with 6000 images per class.
There are 50000 training images and 10000 test images.
A large image database that has over ten million URLs of images that were hand-annotated using Amazon Mechanical Turk to indicate what objects are pictured.