It's probably different for you but this is how I do it:

-Open up the program that came with the Camera (I mainly use zoombrowser but my other program works as well)
-Select the pictures
-Click on Camera & Memory Card
-Click on Upload Images

For my Sony, you can just drag it back into the folder but it won't work if they were edited. If they were turned sideways, they have to be turned back before they upload back onto the memory card.