With the exception of a limited number of graphics references, external files you reference in your template code are not automatically exported with your project because Help+Manual does not know about them. There are two ways to solve this problem:
Nowadays you will almost always choose an HTML skin to publish your project to WebHelp or HTML Help/CHM. A skin is a special kind of Help+Manual project without topics that only stores your HTML templates and all the settings relevant for HTML output to these two formats. When you choose a skin, the templates and settings in the skin completely replace those in your project.
Normally, a skin is pre-designed and you don't need to change anything. However, if you do want to change something, you must do all your editing in the .hmskin skin file. Editing in your Help+Manual project won't have any effect because those templates and settings are not used.
To edit a skin, make a copy of the .hmskin skin file in your project folder and then open it in Help+Manual by selecting .hmskin as the file type to open in the Open dialog. All the templates and settings are in the same places as in a normal Help+Manual project.
Exception: HTML Export Options
The HTML Export Options section is not stored in skins and needs to be edited in your project.
The easiest way to ensure that graphics files and other files referenced in your HTML templates are located and exported correctly is to add them to your project's "Baggage" in Project Files > Baggage Files in the Project Explorer. Then you can use any tag references you like and you don't need to worry about whether the files will be exported and integrated in your output.
All files in the Baggage Files section are integrated in your project automatically and can be referenced in your template code without any path information.
See Using Baggage Files for more information and instructions.
In WebHelp you must manually copy the files to your output directory if you have not added them to the Baggage (see above). The only exception to this are image files referenced in supported tags, which are exported automatically.
In HTML Help you need to tell the compiler to include the files in the CHM file. Proceed as follows:
1.Copy the external file(s) to your project directory (the directory containing your .hmxz or .hmxp project file).
2.In the Project Explorer go to Configuration > Publishing Options > HTML Help > Extended .HHP Settings.
3.In the Additional Settings editing box add the following entries:
Don't add a second [FILES] header if one already exists. Enter each external filename on its own line below the [FILES] header and precede it with the ..\ relative path reference. This relative path reference is necessary because the project is published from a temporary subdirectory in the project directory, so files in the project directory are one level up. If your files are stored elsewhere you need to adjust the path accordingly.