Validate and normalize a screenshot output format. Falls back to
PNG if the requested format is a video container, and downgrades
JPEG → PNG when transparency is required (JPEG has no alpha).
Returns the effective format to encode and a flag indicating
whether any normalization happened (for telemetry / toasts).
Validate and normalize a screenshot output format. Falls back to PNG if the requested format is a video container, and downgrades JPEG → PNG when transparency is required (JPEG has no alpha).
Returns the effective format to encode and a flag indicating whether any normalization happened (for telemetry / toasts).