How do you download pictures off of a Samsung Galaxy cell phone onto a computer?

I have a cell phone that has a bunch of pictures I need on my computer (a Samsung Galaxy) and when I plug it into my mac, nothing happens. I've done it before but I forgot what I did. It had something to do with changing settings on the phone. Can you help me?|||First you need to make sure you have the USB drivers installed for the phone. If you have connected it before then we will assmue that is already done. Next connect your phone to your laptop. If you get a screen asking you to select the USB mode then choose "Mass Storage". You should see a little USB icon pop up at the top left corner of the screen on you phone. Pull the notification (window shade) bar down and you should see a selection that says "USB Connected". Click on this and then you will get a screen asking if you want to mount the SD card. Go ahead and do this. You should now be able to see the drive letter (2 new drive letters if you have an external SD card installed) in Windows. At this point you should be able to access the files on your phone.