ISSUE 

You have "portrait" oriented images and they look poorly cropped in the gallery intro animation.

SOLUTION

In Step 3 --> Options tab: Uncheck "Force crop" option for the intro animation album

SIDE EFFECT

Depending on the theme you chose, the uncropped images may not have a custom fit in the intro animation.

REMEDY

A) Crop your images but control how your images are cropped; select the album used for the intro animation and click Modify album pages (on General tab in Step 3) and then, on the Other tab in Step 2, select an appropriate crop option for each image individually.
   OR
B) In Step 4 --> General tab: Choose another theme, such as Trio-BurntGold, that is not impacted by the orientation of the images
   OR
C) In Step 4 --> Customize tab --> Intro Flash Animation (on the left) --> ImageFile: Delete the path for the graphic used for the intro animation background. Or, if you want to be more creative, you can pick a custom graphic of your own choosing, edited or created outside of Shozam).