diff --git a/README.md b/README.md
index 8030aad..9c80d57 100644
--- a/README.md
+++ b/README.md
@@ -164,7 +164,7 @@ On Android, the tag must be a local image or video URI, such as `"file:///sdcard
 
 On iOS, the tag can be any image URI (including local, remote asset-library and base64 data URIs) or a local video file URI (remote or data URIs are not supported for saving video at this time).
 
-If the tag has a file extension of .mov or .mp4, it will be inferred as a video. Otherwise it will be treated as a photo. To override the automatic choice, you can pass an optional `type` parameter that must be one of 'photo' or 'video'.
+If the tag has a file extension of .mov or .mp4 (lower or uppercase), it will be inferred as a video. Otherwise it will be treated as a photo. To override the automatic choice, you can pass an optional `type` parameter that must be one of 'photo' or 'video'.
 
 It allows to specify a particular album you want to store the asset to when the param `album` is provided.
 On Android, if no album is provided, DCIM directory is used, otherwise PICTURE or MOVIES directory is used depending on the `type` provided.
diff --git a/src/CameraRoll.ts b/src/CameraRoll.ts
index b0769c6..684945a 100644
--- a/src/CameraRoll.ts
+++ b/src/CameraRoll.ts
@@ -178,7 +178,7 @@ export class CameraRoll {
 
     if (type === 'auto') {
       const fileExtension = tag.split('.').slice(-1)[0] ?? '';
-      if (['mov', 'mp4'].indexOf(fileExtension) >= 0) type = 'video';
+      if (['mov', 'mp4'].indexOf(fileExtension.toLowerCase()) >= 0) type = 'video';
       else type = 'photo';
     }
     return RNCCameraRoll.saveToCameraRoll(tag, {type, album});