When is sizeof(cl_mem) in clSetKernelArg not cl_mem?

Hi,

I see that many people use sizeof(cl_mem) in clSetKernelArg for multiple clSetKernelArg calls.

Does this just mean that the arguments are all memory buffers as opposed to image? So if all my files just use memory, can I always use cl_mem? Would I ever put the name of the memory object in sizeof(variableName)?

Thanks for any elaboration on this point.