diff --git a/matrix-sdk-android/src/main/java/im/vector/matrix/android/api/session/room/model/message/ImageInfo.kt b/matrix-sdk-android/src/main/java/im/vector/matrix/android/api/session/room/model/message/ImageInfo.kt
index 513a4366..69e88e05 100644
--- a/matrix-sdk-android/src/main/java/im/vector/matrix/android/api/session/room/model/message/ImageInfo.kt
+++ b/matrix-sdk-android/src/main/java/im/vector/matrix/android/api/session/room/model/message/ImageInfo.kt
@@ -21,7 +21,7 @@ import com.squareup.moshi.JsonClass
 
 @JsonClass(generateAdapter = true)
 data class ImageInfo(
-        @Json(name = "mimetype") val mimeType: String,
+        @Json(name = "mimetype") val mimeType: String?,
         @Json(name = "w") val width: Int = 0,
         @Json(name = "h") val height: Int = 0,
         @Json(name = "size") val size: Int = 0,