diff --git a/Demos/Host/StillImageHost/StillImageCommands.h b/Demos/Host/StillImageHost/StillImageCommands.h
index 2ac6afd8bd..38bbadf706 100644
--- a/Demos/Host/StillImageHost/StillImageCommands.h
+++ b/Demos/Host/StillImageHost/StillImageCommands.h
@@ -54,13 +54,21 @@
 		/** Timeout period between the issuing of a command to a device, and the reception of the first packet */
 		#define COMMAND_DATA_TIMEOUT_MS        5000
 		
-		/** Used in the DataLength field of a PIMA container, to give the total container size in bytes.
+		/** Used in the DataLength field of a PIMA container, to give the total container size in bytes for
+		 *  a command container.
 		 *
 		 *  \param params  Number of parameters which are to be sent in the Param field of the container
 		 */
 		#define PIMA_COMMAND_SIZE(params)      ((sizeof(PIMA_SendBlock) - sizeof(PIMA_SendBlock.Params)) + \
 		                                        (params * sizeof(PIMA_SendBlock.Params[0])))
 
+		/** Used in the DataLength field of a PIMA container, to give the total container size in bytes for
+		 *  a data container.
+		 *
+		 *  \param datalen  Length in bytes of the data in the container
+		 */
+		#define PIMA_DATA_SIZE(datalen)        ((sizeof(PIMA_SendBlock) - sizeof(PIMA_SendBlock.Params)) + datalen)
+
 	/* Type Defines: */
 		/** Type define for a PIMA container, use to send commands and receive responses to and from an
 		 *  attached Still Image device.
@@ -71,7 +79,7 @@
 			uint16_t Type; /**< Container type, a value from the PIMA_Container_Types_t enum */
 			uint16_t Code; /**< Command, event or response code of the container */
 			uint32_t TransactionID; /**< Unique container ID to link blocks together */
-			uint32_t Params[4]; /**< Block parameters to be issued along with the block code */
+			uint32_t Params[4]; /**< Block parameters to be issued along with the block code (command blocks only) */
 		} PIMA_Container_t;
 	
 	/* Enums: */
diff --git a/LUFA/ChangeLog.txt b/LUFA/ChangeLog.txt
index 036e0314c7..3622f66e96 100644
--- a/LUFA/ChangeLog.txt
+++ b/LUFA/ChangeLog.txt
@@ -14,6 +14,7 @@
   *  - Changed GenericHID device demo to use the LUFA scheduler, added INTERRUPT_DATA_ENDPOINT and INTERRUPT_CONTROL_ENDPOINT compile
   *    time options
   *  - All comments in the library, bootloaders, demos and projects have now been spell-checked and spelling mistakes/typos corrected
+  *  - Added new PIMA_DATA_SIZE() define to the Still Image Host demo
   *
   *  \section Sec_ChangeLog090401 Version 090401
   *