I used the Inky impression eInk display to automatically show pictures I send it via email! Made with a Pi Zero W, a Pimoroni inky impression and an IKEA RIBBA picture frame (10x15cm) which fits (almost 😅) perfectly! A cron job checks for new Mail every 5 minutes, automatically resizes the attached image to fit the eInk display’s resolution and displays it. You can also select the picture from your smartphone.
See sample code on my github: GitHub - fapeg/eink_picture_frame