Yes you can! From the left toolbar, select sticker, then the category for the desired artwork. All available stickers are displayed to the left and then can be dragged onto the calendar.

Adding sticker to Event Dates

Step 1:

Select desired sticker category.

Step 2:

Select the month with the event.

Step 3:

Click on desired sticker for it to appear on the calendar.

Step 4:

Resize the sticker then drag it to the desired date.

NOTE: Although stickers don't have an option to crop, they can be resized similarly to photos. Click to learn more about resizing photos.