Choose one job for the effect
An effect can indicate that an image is interactive or help explain a change of state. Keep its purpose clear. Captions and links should remain available on a touch screen, with a keyboard and when motion is reduced.
Keep the original proportions
Use a predictable image container and avoid changing the page height when an effect begins. Check the focal point at different screen widths. A decorative crop should not remove the part of the image that the caption describes.
Leave room for a quiet version
Treat the still image as a complete presentation. Motion can add a finishing touch, but it should not reveal information that is otherwise hidden. Use the layout lab to compare a calm palette and a compact viewport before adding transitions.