The reserved named blocks defined for annotation marks and their associated structures and usage are as follows:
| Named Block | Associated Structure | Usage |
| OiAnoDatFor lines: | AN_POINTS | List coordinates for lines and freehand marks. |
| For images: | AN_NEW_ROTATE_STRUCT | Hold scaling and resolution information for image marks. |
| OiFilNam | AN_NAME_STRUCT | Hold file name for image marks. |
| OiDIB | AN_IMAGE_STRUCT | Store DIB data. |
| OiGroup (required) | STR | Create sets of marks (required). |
| OiIndex (required) | STR | Assign unique number, originating at 0, for each mark. To facilitate easy application control, the next available number is generated by incrementing by 1 the number just assigned and storing it in the default OiIndex mark. |
| OiAnText | OIAN_TEXTPRIVDATA | Display text annotation marks. |
| OiHypLnk | HYPERLINK_NB | Turn mark into a hyperlink. |
Note: The Hyperlink annotation type is available with Imaging for Windows Professional Edition (read/write) and Imaging for Windows 98 (read only).