you could previously only use the column index in the file naming convention to identify the source column of the exported file e.g.
which would then name the exported files this way:
Files with the suffix 0002 indicates that it was exported from the 2nd column (ThumbnailPhoto), and 0003 from the 3rd column (LargePhoto).
From version 3.17 onwards, you can now use the column name in the naming convention, using the <%columnname%> tag e.g.
The exported files are then named this way:
which is more meaningful.