Does this gap happen on the entry page itself or when you view the code on a layout?

If it's on the entry itself, the height of the cell that contains the image is at 280px by default (the same number as the one on the D.Va sample!), so you may have to adjust it accordingly. Otherwise, I can look at the code to see what's up.

If happens on your journal's layout, you'll have to tweak the layout itself. If you toss me the layout code, I can try to fix it for you!