You can not use keyboard TAB to move from textBox 'Tooltip' to textBox 'Alternate text'.
When You have added a picture there is no preview image. You can se it 'flash' then it disappear.
GNOME-panelen 2.28.0
KomPozer 0.8a4 (20081229)
Ubuntu 9.10 Karmic Koala
I would like to confirm this behaviour. I did not see this in 0.7 version, but I am now seeing in the 0.8b3 version.