To empty the destination directory before copying graphics files for HTML:
[Automation] WrapAndShip=Yes ; EmptyGraphPath = No (default, leave graphics files in place) ; or Yes (empty GraphPath directory before copying) HTML only EmptyGraphPath=Yes
Note: For JavaHelp and Oracle Help, alternate settings apply; see §20.3.6.2 Letting DITA2Go set up the directory structure and copy files.
EmptyGraphPath takes effect when WrapAndShip=Yes, CompileHelp=Yes, or FTSCommand=path\to\indexer (see §44.10 Gathering and processing Help-system files).
When EmptyGraphPath=Yes, provided [Graphics]GraphPath does not point to the project directory, DITA2Go deletes the entire contents of the GraphPath directory before copying files into it. However, if either of the following is true, DITA2Go does not delete anything, regardless of the value of EmptyGraphPath:
If WrapPath points to the same directory as GraphPath, DITA2Go does not delete files unless both EmptyWrapPath and EmptyGraphPath are set to Yes; see §44.6 Assembling files for distribution.
When EmptyGraphPath=No (the default), DITA2Go leaves the prior contents of the GraphPath directory in place.