Show a fallback placeholder if the image is unreachable.

[tinyjin]

When an animation image is unreachable, the viewer currently shows nothing, whereas other Lottie players can display a default placeholder. Providing a placeholder would help users recognize that the image is unavailable.

Since the ThorVG engine itself is not responsible for placeholders, this functionality can be handled at the ThorVG viewer level to improve usability.

ThorVG	Lottie Viewer

TO-BE