No matter what method you choose to make your calendars, you'll want to choose 12 pictures, one for each month of the year. I usually take pictures from the year before. If I use pictures taken in July of 2019 for my July 2020 calendar, for example, it is more likely to have a summery feel that will fit well with that month on the calendar.
Choose a Flip Photo Frame
Once you've chosen an ideal flip frame for your calendar, check on the size of the photos it holds. This will determine the size you need to print your calendars.
Make a Photo Calendar in Canva
Using Canva is my favorite method for making a photo calendar. They have many photo calendar templates to choose from. Choose a template from the Canva calendar templates available.
Remove the photos used in the Canva template to avoid being charged for them later. Upload your photos into Canva and drag them from the uploads section into the placeholder for the images on the calendar templates.
Make any wanted adjustment to the filters used on the photos (or remove them). Make all other wanted adjustments to the fonts and other design elements on the calendars.
Choose a photo and open it in Photoshop. Run the script with the photo open to work it into the calendar design.
Make any wanted adjustments and then save and download that month's calendar. Repeat the process with new pictures and new months.
Putting the calendar together
Download the 12 months of calendars and print them out in the size needed for your particular flip frame.
Place the January and February calendars face up and back to back. Slip them into the first page of the photo flip frame.
Place together the March and April calendars in the same way and slip them into the second page on the photo flip frame.
Continue with the rest of the months of the year, until you've completed your calendar.
Notes
Calendars can also be made in Google Calendars by choosing the print option from the settings menu in Google Calendars after choosing a monthly view. Rather than doing a direct print, the calendars can be saved as a PDF with a transparent background. A photo can be later added to the calendar in a photo editing program.