Signal
Creative Workflow

Media validation rules

What Signal checks before allowing media to publish: format, alt text, and provider-safe sizing.

Last updated June 14, 2026

Before media can publish, Signal validates it. The checks exist to prevent two failure modes: publishing inaccessible media (no alt text) and publishing media a platform will reject (wrong format or too large).

Checks

  • ·Alt text — required where the platform expects it; a missing value blocks the post.
  • ·Format — the image must be a supported type.
  • ·Size — oversized images are reduced to a provider-safe derivative; if it can't be made compliant, the post is blocked.