An image capturing apparatus capable of guaranteeing the authenticity of contents while reducing the calculation load of a hash value of an image file. The image capturing apparatus generates an image file, and performs processing for reducing a file size of the image file. A hash value generation section calculates a hash value by applying a hash function to the processed image file. Reduction processing information indicating a method of reducing the file size is generated, and the image file, the hash value, and the reduction processing information are transmitted in a state associated with each other, to a management system that registers data associated with the image file including the hash value in a blockchain.