1. A method of displaying moving image thumbnails comprising: creating decoding threads and drawing threads for respective compression-coded moving image files, and switching the threads for processing, the decoding threads each being for decoding a moving image file and storing generated texture data in a corresponding texture buffer, the drawing threads each being for reading the texture data from the corresponding texture buffer and generating and storing image frame data in a corresponding frame buffer; and reading the image frame data on the plurality of moving image files from the respective corresponding frame buffers, and outputting the image framed data to a display device in parallel, wherein the switching for processing includes: detecting the amount of the texture data that is stored and yet to be read in the texture buffers when starting to process the decoding threads; and stopping decoding-related processing of the decoding thread when the amount of the texture data thereof exceeds a predetermined value, and switching processing to other threads.