If there is marked (selected) text an one writes, the text will be overwritten
(and the new text gets its properties (formats)).
Unfortunately for pictures this doesn't hold.
1. (is)
Do Insert - Picture - From File
Dialog for inserting pictures openes.
Select file and insert picture.

2.1 (is)
Select the picture.
Do Insert - Picture - From File
Dialog for picture-properties opens.

2.2 (should)
Should open picture-insert-dialog and inserting a picture should replace the
selected one, taking its size, wrap-properties and so on.