Image data to store by an *image_store* instruction.
*Size:* depends on :ref:`dmask<amdgpu_synid_dmask>` and :ref:`d16<amdgpu_synid_d16>`:
*:ref:`dmask<amdgpu_synid_dmask>` may specify from 1 to 4 data elements. Each data element occupies either 32 bits or 16 bits depending on :ref:`d16<amdgpu_synid_d16>`.
*:ref:`d16<amdgpu_synid_d16>` specifies that data in registers are packed; each value occupies 16 bits.
