I realized that NextGEN gallery removes Exif data after image rotation while I was having trouble on uploading huge images this morning. Automatically image rotation is a good feature for NextGen gallery WordPress plug in. Sadly, it will remove Exif data that was embedded inside the images. There is nothing I can do for those images that already rotated by NextGen since I don't have the original images with me anymore. Currently I am using version 1.4.3. Hoping the developer will fix it soon. The temporary solution will be manually rotate the image with other software, such as GIMP or XnView, that can remain the Exif data before uploading to the website.