You can Insert a Picture into a container field using the Insert>Picture menu item or the Insert picture script step associated with the container field or other button. Do not check the "store only a reference" option.
In FMP 10, uncheck the 'store only a reference to the file' and it will be embedded. I'm not sure about other versions.
Depending on the size of the images to be stored...
Make a copy of the database, note the size.
Import ten images (of the same size to be used)
Check the size.
Multiply by a year's worth of records and make your decision on storing internally.