It's easy to source content you are free to use by searching the web through Viraltag. Search through Bing brings up images that area all available to be used with a Creative Commons license.
1. Click on the '+' button on the left hand panel of the screen or select 'Create a Post'
2. This will open a window allowing you to choose where you would like to upload your images from. Click on the Search icon on the left of the window.
3. Type the search parameter in the search bar and hit the "Enter" key on your keyboard. You will see all the options that appear under the search parameter. Click on 'Upload' after selecting one/multiple images. You can then proceed to schedule from here.