IconClickFallbackImage needs width and height
<IconClickFallbackImage> should have width and height attributes
Short answer
VAST 4.2 added <IconClickFallbackImage>. Without width and height, the player cannot reserve space for the fallback image.
`<IconClickFallbackImage>` (added in VAST 4.2) should carry `width` and `height` attributes so the player knows the dimensions of the fallback image before fetching it.
Why this matters in production
This rule is a strong risk signal. Tags with this issue often still parse, but they become brittle across SDKs, SSAI resolvers, and CTV environments. Ambiguous rules matter because undefined behavior shifts between vendors. Fixing them reduces the chance that two standards-compliant systems interpret the same tag differently. Affected scope: VAST 4.2 and 4.3.
How to fix
Add width and height attributes to <IconClickFallbackImage> so the player knows the dimensions before fetching.
VAST-4.2-icon-fallback-image-width-height and other issues instantly.Open the VAST tag validator →