This may have already been covered in a previous post, but I have not found it. If so please delete.
I, and many others that I have seen recently, have had problems with pictures being posted sideways from the original. Here is a fix that I have found. I am using a Samsung Galaxy S8, I do not know if this works on other platforms.
When attaching photos, before selecting "send",
click "edit",
then click "auto",
then "save"
and finally "send".
