how can I download the images off iCloud to my mac

Where are the images? In Photos or iCloud Drive? For Photos, if you are using OS 10.10.3 or above, open Photos, then go to Photos/Preferences/iCloud and set up syncing. Then go to System Preferences/iCloud or Apple ID, sign in, and check Photos syncing.

 You can also do a manual download at iCloud.com/Photos. Hold down the command key while selecting the photos. Then click Download. Another option is to select a Moment, then click the Share button, and then cancelling the Share. The photos should remain selected.

For iCloud Drive, go to the Finder Sidebar/Favorites, select the image in iCloud Drive, and drag it to the desired location. If iCloud Drive isn't visible in the Finder Sidebar, go to finder/Preferences/Sidebar/Favorites and check iCloud Drive.