If your help volume uses graphics, the image files are typically stored in a separate directory for convenience. However, you may choose to store them in the same location as your volume.htg file.
A run-time help file does not include actual graphic images. Instead, it contains a "reference" to the location of each graphic file. When you run HelpTag, the dthelptag compiler incorporates the relative path names of the graphics files into the help volume.
When the help files are installed, the graphics files must be in the same relative position as when the run-time file was built. Otherwise, the help volume will be unable to locate the graphics files. For example, if your graphics files are in a subdirectory named graphics one level below your volume.htg file, then your installation package must preserve that relative position. The graphics files must be placed in a subdirectory named graphics one level below the volume.sdl file.