diff --git a/resources-generator/src/main/kotlin/dev/icerock/gradle/tasks/GenerateMultiplatformResourcesTask.kt b/resources-generator/src/main/kotlin/dev/icerock/gradle/tasks/GenerateMultiplatformResourcesTask.kt
index 0da87562..40c24132 100644
--- a/resources-generator/src/main/kotlin/dev/icerock/gradle/tasks/GenerateMultiplatformResourcesTask.kt
+++ b/resources-generator/src/main/kotlin/dev/icerock/gradle/tasks/GenerateMultiplatformResourcesTask.kt
@@ -99,6 +99,7 @@ abstract class GenerateMultiplatformResourcesTask : DefaultTask() {
     @get:Input
     abstract val strictLineBreaks: Property<Boolean>
 
+    @get:Optional
     @get:Input
     abstract val allowWebpImageFormat: Property<Boolean>