Dropbox is a cloud storage service which was founded by Drew Houston and Arash Ferdowsi in 2007. File synchronization is the main function of Dropbox. DropBox has a "Camera Upload" feature that automatically upload the photos and videos from your Android phone to your Dropbox account. You can sync all your photos with DropBox by turning ON the 'Camera Upload' feature. It will automatically sync new photos, videos and files whenever they are detected. Dropbox allows you to work offline and will then sync the new files after connecting to Internet again.
Make sure you have downloaded the latest version of the Dropbox app on your Android phone. During the initial setup, you will be prompted to select your "Camera Upload" settings. It allows you to choose to upload photos and videos using Wi-Fi and/or your cellular data plan. Once you enable the "Camera Upload", then automatically your photos and videos will be uploaded to Camera Upload folder within Dropbox. Now any time you launch Dropbox from your Android phone, it will automatically upload any photos and videos you have taken since last time the app was open.
You can install PicBackMan's Dropbox uploader for Mac from the website and start backing up photos and videos.