What is the max sd card size for the LG optimus dynamic
LG on its website here has featured the specifications for your device, and the relevant one is:


  microSD™ Memory Slot   &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;   Supports up to 32 GB memory card**


Now you can buy the micro-SD card of size up to 32GB.