While your images may display correctly on your mobile device or computer, they may actually be rotated. Once you upload them to Canvas, Canvas does not provide a way to rotate them to the correct orientation. For more information on this issue, see: https://community.canvaslms.com/t5/Idea-Conversations/To-be-able-to-Rotate-an-image-inside-the-Rich-Content-Editor/idi-p/343534
For assistance, contact the IS Service Desk.