The easiest way to insert an image in your document is to
    use the  Add image button found in the toolbar. After doing that, you still
    have to specify the graphic file which is the source of the image.
    Generally this is done by first clicking on
    Add image button found in the toolbar. After doing that, you still
    have to specify the graphic file which is the source of the image.
    Generally this is done by first clicking on  the image placeholder icon and then
    using the Attributes tool to specify the graphic file. DocBook
    example: clicking on the image placeholder selects the corresponding
 the image placeholder icon and then
    using the Attributes tool to specify the graphic file. DocBook
    example: clicking on the image placeholder selects the corresponding
    imagedata element. Then you have to specify a fileref
    attribute for this element.
Inserting image in a document is a very common task that's why there are more convenient ways to specify the graphic file which is the source of the image:
In both cases, this displays a specialized dialog box.

The "Source location" field allows to specify the graphic file which is the source of the image. The "Destination location" field allows to specify how this graphic file is to be referenced in the document. Note that this dialog box requires specifying URLs and not filenames.
For example,
    let's suppose that your document is found in the docs/ directory
    and that all your graphic files are found in the docs/images/
    subdirectory. If you want to insert an image pointing to
    docs/images/logo.png, then simply make sure that the
    "Reference as" radio button is checked.
Now let's suppose you
    want to insert C:\tmp\screenshot.png in your document. You'll
    probably want to copy this file to docs/images/ subdirectory and
    give it a more meaningful name (e.g. login_dialog_box.png). This
    is done by checking "Copy to" and specifying
    "images/login_dialog_box.png" in the "Destination
    location" field.