There are two types of Memorex.Domain.Notes in Memorex. The first type (called "text notes") consists of a single line in a Memorex.Domain.Deck Markdown file which contains either the bidirectional or unidirectional delimitter (which are by default "⮂" and "→", respectively). The primary key of a text note is a UUID which is a hash of the note content (together with the note category, which is the name of the Markdown file if this deck is a directory which contains multple Markdown files). Notes are flagged when the Memorex.Deck parsing starts (via mix memorex.read_notes), and any Memorex.Domain.Note which does not show up in the current parsing of the Memorex.Domain.Deck is purged (so if the Memorex.Domain.Note has been edited in the Markdown file, it will be deleted and re-created on the next reading/parsing of the Memorex.Domain.Deck).

The second type of Memorex.Domain.Notes are "image notes". An image file is placed in a Memorex.Domain.Deck directory on the filesystem. A text file with the same name as the image file (but with the extension ".txt") is placed as a sibling to the image file. The text file contains the answer to the image file. The UUID for image notes is a hash of the contents of the image, the image file path, and the contents of the text file, so the UUID will change if the image file itself is changed, the file is moved, or the answer in the text file is changed. Image notes can have the extension ".jpg", ".jpeg", ".png", ".webp", ".svg", or ".gif".