1. An image processing apparatus for editing an image by using content images different in image size for the same content image depending on applications, the image processing apparatus comprising: a data acquiring unit configured to acquire content image data having a predetermined image size; an image processor configured to generate image data of an image size corresponding to each application based on the acquired content image data, wherein the generated image data is not separately installed in the image processing apparatus; and a data storage device configured to store the acquired content image data and the generated image data; wherein the data acquiring unit acquires the content image data before the content image data is utilized by any of the applications; and wherein the content image data includes background image data to be composited with a video image including a user as an object, and the image processing apparatus further includes a display device configured to display the background image data in a size corresponding to each application.