While we do not currently have an app for computers, you can still effectually share photos from your computer, via iCloud or Google Photos.
If your photos are stored in your iCloud library, it will sync with the frame (the photos don't necessarily need to be stored locally on your phone). To make sure your iCloud photos are syncing, first check to see if they appear in your Photos library on your iPhone. If you haven't enabled photo syncing you can do so in your iPhone settings by clicking on iCloud and then turning Photos syncing on.
If the photos are saved on your computer and not on your phone, you may need to turn on photo syncing in your iCloud settings on your computer. To do this, open Photos and click on Preferences and enable your iCloud Photo Library. Then open Photos on your phone to make sure the photos appear there first. Next time you open the Aura App you should see all of your iCloud photos and albums in the app. It will automatically update to upload any new photos you take on your iPhone or save to your Photos library on your computer.
Alternatively, the app includes a Google Photos integration which allows you to connect your Google Photos account in the Aura App. Google photos offers unlimited storage and can store all of your photos from your Computer which can then be shared to the frame. When you open the Aura App, scroll down to where you see "Google Photos - Link Account" and select "Add Account". You are then invited to enter your Gmail address and password. Once this is complete you'll have access to all your Google Photos.