1. An image transferring apparatus, comprising: a storage unit, adapted to store image data; an image data transfer instruction unit, which includes a button for instructing image data transfer, adapted to enable a user to enter an instruction to transfer the image data; a display unit, adapted to display a first screen to enable a user to select between (1) automatically selecting and transferring only image data stored in said storage unit that have has not previously been transferred and (2) automatically selecting and transferring all image data stored in said storage unit, and to display a second screen to enable a user to select between (1) automatically transferring image data in response to connecting said image transferring apparatus to another apparatus and (2) automatically transferring image data in response to an instruction to transfer entered by the user with said image data transfer instruction unit; and a transfer control unit, adapted to perform control to automatically transfer the image data, and (1) to judge a selection selected from the first screen displayed by said display unit, and if the selection to automatically select and transfer only image data stored in said storage unit that have not previously been transferred is made, perform control to automatically select and transfer only the image data stored in said storage unit that have not previously been transferred based on transfer history information, and if the selection to automatically select and transfer all image data stored in the storage unit is made, perform control to automatically select and transfer all the image data stored in said storage unit regardless of the transfer history information and (2) to judge a selection selected from the second screen displayed by said display unit, and if the selection to automatically transfer image data in response to connecting said image transferring apparatus to the other apparatus is made, perform control to automatically transfer image data in response to connecting said image transferring apparatus to the other apparatus, and if the selection to automatically transfer image data in response to an instruction to transfer entered by the user with said image data transfer instruction unit is made, perform control to automatically transfer image data in response to an instruction to transfer entered by the user with said image data transfer instruction unit.