There are plenty of programs that will scan for duplicate files. You can find one that would work with a Mac and plug your SD card into your computer. From there select the SD card through the program and allow it to run. It should find and take care of any duplicate files.
CrackBerry is in no way Affiliated with BlackBerry. We take pride in our unbiased content, however do occasionally receive free products from vendors that we review or discuss. For more info click here.