To display attachments in a grid, rather than one right after the other in a list, use the Drawing() function within a picture type field to display attachments in reports. But you will need to do special formatting for the columns.
In order to setup Columns to display attachments in a two-column-wide layout, setup two tables embedded into fields in the parent table and use filtering to configure how they display. This method may not work for everyone depending on the desired look of the report. One possible outcome is that there can be more attachments in the right column than the left. To counter, this you can engineer a value for the ID or notes field to filter on.
NOTE: It might be possible to do this with three or more columns but you would need to engineer IDs to filter on.