In the power point program, there is an icon in the toolbar which allows the operator to rotate the orientation of an image. I cannot find that icon, and cannot therefore change the image from horizontal to vertical orientation. Help!
Right click on your image and select Rotate in a context menu, then press left mouse button on any image corner and move it => it should rotate the image
If you want to set the rotation angle numerically, then :
Right click on the picture - Position and Size (item) - Rotation (TAB) - adjust the Rotation angle in Degrees unit.
This function is available from the Format menu too:
Format - Object and Shape - Position and Size
Of by a simple F4 hotkey hitting. (After selecting the image.)