diff --git a/mirai-core/src/androidMain/kotlin/net/mamoe/mirai/utils/ExternalImageAndroid.kt b/mirai-core/src/androidMain/kotlin/net/mamoe/mirai/utils/ExternalImageAndroid.kt
index 205f53f9b..71d3764e2 100644
--- a/mirai-core/src/androidMain/kotlin/net/mamoe/mirai/utils/ExternalImageAndroid.kt
+++ b/mirai-core/src/androidMain/kotlin/net/mamoe/mirai/utils/ExternalImageAndroid.kt
@@ -35,7 +35,7 @@ import java.net.URL
  */
 @Suppress("UNUSED_PARAMETER")
 @Throws(IOException::class)
-fun Bitmap.toExternalImage(formatName: String = "gif"): Nothing {
+fun Bitmap.toExternalImage(formatName: String = "gif"): ExternalImage {
     TODO()
 }