I am not exactly sure what you mean by opening a png graph . However , you can do something like this :
FilesList = Files In Directory(Your File Path) ; // This should give you list of all the files in the directory
for(i = 1 , i <= N Items(FilesList) , i++,
FileName = FilesList[i];
) ;
Now you have in FileName , the name of the file which you can use to append to your destination while saving
Best
Uday
Best
Uday