Problem uploading pictures....help appreciated.

I have uploaded lots of pictures on this forum in the past before with no problems.
Since upgrading to windows 10 though I have had trouble uploading some pictures the right way up/around.
I get them the right way up in the windows picture viewer but when I go to upload them they upload in the original way. For example if I have taken a picture with the camera on it's side I will rotate the image in the photo viewer so it is the right way up. However when I up load it to the forum it is uploaded in it's pre rotated form so it is not the right way up.
I can't seem to correct this in the "preview section" when posting a thread.
Hoping someone can help out here as it is driving me batty.

After rotating it you have to save it as it is only rotated in the viewer not in the original file.

Thanks Bohdan.