[gd~...] This code places graphics data at the current cursor position. Normally, this command is entered into your document when you use the Picture: Add command from the DBT Layout menu to insert a graphics file from disk, or when you have imported a .dxp file from NimPro that includes tactile graphics. (Note: gd replaces the obsolete pi command.)
Layout: Picture: Add inserts the tactile graphic picture. Other items in the Layout: Picture menu set the picture alignment (left, right, or center). They can be used when the cursor is positioned just before a [gd~...] code. Getting this position right is most easily done in Coded View (Alt + F3).
It is not practical to enter a gd command manually, because the full graphic image is included in the command as a parameter, and that data is both specially coded and lengthy.
For the same reason, the graphic data is not shown in the DBT coded view.
Duxbury has developed a program called QuickTac which can be used to create picture files to be inserted into DBT documents. (QuickTac was still a free download from the Duxbury website as of this writing.)