clarify information about using an image in the running header and footer [skip ci]

1 files changed, 3 insertions, 2 deletions

diff --git a/docs/theming-guide.adoc b/docs/theming-guide.adoc
index b815478d..601584fd 100644
--- a/docs/theming-guide.adoc
+++ b/docs/theming-guide.adoc
@@ -3947,8 +3947,9 @@ One exception to this rule are inline images, which are described in the next se
 ==== Images
 
 You can add an image to the running header or footer using the AsciiDoc inline image syntax.
-Note that the image must be the whole value for a given position (left, center or right).
-It cannot be combined with text.
+The image target is resolved relative to the value of the `pdf-themesdir` attribute.
+If the image macro is the whole value for a column position, you can use the `position` and `fit` attributes to align and scale it relative to the column box.
+Otherwise, the image is treated like a normal inline image, for which you can only adjust the width.
 
 Here's an example of how to use an image in the running header (which also applies for the footer).