I'm going back to a project where I need RapsberryPi, but the last attempt to create an image is to save it in SdFlash, using the DD command, the process took hours to complete, I left and did not count the time but I will do it again this weekend and update this doubt.
It's important to note that I'm using the Mac, so far as I know the commands of Shel, it does not make any difference, and this one in particular has no bug that could lead to this delay.
Another important data, the image used was created with 32GB.
The card is a Kingston SD HC 32GB