There is provided an information processing device which comprises a transparency adjustment unit to adjust transparency of a watermark image which is to be added to a main image to prepare data of a first image having first transparency and data of a second image having second transparency, wherein each of the first and second images corresponds to the watermark image and the first transparency of the first image is higher than the second transparency of the second image. The information processing device further comprises an overlap processing unit to generate data of an overlap image of the main image, the first image and the second image such that the second image, the main image and the first image overlap with each other in bottom-to-top order.