From the Bodlian broadside site
Jim Carroll
"The cheapness of ballad printing is reflected in the collage-like composition of the broadsides: to make up a full sheet, the printer would choose a text and sometimes an illustration -- though not necessarily an illustration made on purpose for that ballad. If the sheet was to contain more than one ballad, the printer decided which songs to include from the thousands available without copyright. The results will be seen by any user of this database; a single ballad text may appear in many different ballad sheets, juxtaposed with different companion ballads. The same may be said for the woodcut illustrations: a woodcut intended to illustrate one ballad might be used later alongside a different song. These characteristics of broadside ballad publishing have influenced the approach to cataloguing the broadside ballads in this database. The individual ballads and the illustrations are treated as entities within the envelope of the complete broadside sheet. Therefore both broadside sheets and the individual ballads contained in them are searchable."