Whe you connect your Galaxy smartphone to your computer, it should show up in windows explorer. If it doesn't show up after about 30 seconds or so, disconnect, wait about 10 seconds and reconnect.

BTW, It will only show up if there are pics available. If there are no pics, it will not show up.

You cannot do an "upload all" from your phone to a computer. Only pics are uploadable. Some programs with mp3 files have a share or upload feature built into the app. Those files can only be access through the feature that is built into the app. If the app does not have a sharing, upload, or transfer feature (like iTunes), then mp3's cannot be transferred from the phone but can only be downloaded to and deleted from the phone itself.