the problem is in the where clause:
and in the beginning of the select clause:
since the field fld_id exists in both the tbl_bgimg and tbl_menu tables, you need to specify which one to use:
SELECT tbl_bgimg.fld_id.....WHERE tbl_bgimg.fld_id.....
to prevent this issue from happening, i recommend a naming convention that will not allow for duplicate names of columns.
the naming convention I like to follow is to use the table name in the column name.
for example, if i where to create a users table:
or an addresses table: