This is important because I will be submitting it for my visa application (rotated images disqualify you).
The image looks rotated sideways in thumbnail view on my computer, but when I double-click to open it (e.g. in paint or any other basic image viewer/editor), it looks alright! Why might it look rotated in thumbnail view? Note that when the photographer took my photo, it initially showed up sideways on his computer, too. Then, he rotated it to the correct upright profile view, burnt it onto a disc, and gave me the disc.
How can I fix the thumbnail so that it matches the image?