It's easy to upload your own images to your collections. To do this:
- Open up your collection by clicking on it (all of your collections can be seen on the homepage).
- Click the green 'Edit Collection' button in the bottom-right.
- Click the 'Add an Image' button (it looks like a camera)
- You can click 'Upload an Image' to grab an image from your computer, or 'Choose an Image' to pick from the free stock image library Unsplash.
And that's it! See this video for where to find the button: