Here is what I do to upload files.
. Go advanced
. Manage Attachments
. Add Files
. Select Files
. (select files from the list)
. Upload Files
The files uploaded are displayed in the bottom strip. If the files shown here are correct orientation, then your files are fine.
Now for displaying them, you have two options
. Insert all files.
. Insert individual files.
If you use the former, then all files will be displayed without any space between them. That is where the problem starts. The software will try to adjust the files within the width, and it some how auto rotates files here. So avoid this.
Instead insert individual file (using the attachments button in the toolbar. In my window it is third button from left of the top most tool bar of the editing window), and after each file, go to the end and press the "Enter" button. That ensures that each image is inserted in a new line.