You are able to personalize the folders in your library by adding an image to the front of it.
Click on the 3 dots on the top right of the folder and select Edit.
A new window will open for you to add the image you want to use for that folder.
Clicl on 'Upload preview', find the image you want to use, select it and adjust the dimension to the available area.
Finally, when you are ready click on Save Image.
You will now see the image on the folder. Click Save and this will bring you back to the main Library.
Note: By clicking 'Reset preview' you will remove the image added and restore the default view.