An image processing apparatus and method execute instructions contained in multiple threads in parallel. The image processing apparatus decodes code data that is obtained by dividing image data into areas and carrying out a compression process such that the individual areas can be independently decoded. The image processing apparatus includes a first thread generating unit that allocates one execution thread to each independently compressed code, a second thread generating unit that allocates plural execution threads to each independently compressed code, and a control unit that controls the operation of the first thread generating unit and the second thread generating unit. At least part of an execution instruction for decoding the code data into image data is generated by the first thread generating unit or the second thread generating unit.