1. A print apparatus for printing an image on the basis of image data, comprising: input means for receiving image data from a plurality of different image data sources; printing means for printing image on a printing medium on the basis of print data; first print control means for outputting to said printing means print data based on image data from a first image data source of the plurality of image data sources and printing an image; decoding means for receiving compressed image data from a second image data source of the plurality of image data sources, different from the first image data source; image processing means for parallel executing at least color space conversion processing, size change processing, and color conversion processing for the image data decoded by said decoding means; and second print control means for generating print data on the basis of the image data processed by said image processing means, and outputting the generated data to said printing means to print the image.