How do I use Tasker to download web images and set them as my background?
I just messed around with Tasker a little more and found an answer. For anyone who is curious here it is.
 1. Create a new profile set to every 24 hours.
 2. Add a new action
 3. Search for and select HTTP Get
 4. Set the Server:Port to https://source.unsplash.com/2560x1440/?nature/
 5. Set the Mime Type to image/*
 6. Set the Output File to unsplash.jpg
 7. Create a new action
 8. Search for and select Set Wallpaper
 9. Set the Image to unsplash.jpg
That should then change the background to a random image every day at midnight. Please let me know if I have made any mistakes, but from what I can see this works.