Hi,
I can help you get started on this.
It could be possible to do if you follow our themer’s guide:
https://theeventscalendar.com/knowledgebase/themers-guide/
You could move the month view template to your theme.
Then look in the Views directory of the Pro plugin and find the Photo View coding and move that to the bottom of the Month template.
That might get you started, but we are unable to provide much more support on this than that.
Let me know if you have any follow up questions.
Thanks