If the image is displayed correctly on your Mac/PC and rotated in fotocommunity, this is because your image viewer program evaluates the orientation from the Exif data and automatically rotates the image when it is displayed on the monitor. In fotocommunity this automatic alignment is not done.
It is not possible to change already uploaded images. You must therefore proceed as follows:
- Open the original photo in your image editing program
- turn it into the correct alignment
- Save the picture under a new file name on your hard disk
- upload the newly saved image to fotocommunity again.