When you add an attachment to an email/note in Daylite, the attachment is saved in the local copy of Daylite and then synced to the server. Because file attachments are downloaded on-demand, other devices will only download from the server after choosing "Click to Download."
If the file being attached is over 20MB, it is recommended to add it as a file reference instead.
File reference is a file that is not saved to your database, and instead, the path to the file is stored. Any Mac with access to the file path can then view the file either directly or over a network. If you do not have access to where the file is stored, it will not be viewable.