Some image files contain metadata that often includes the native size and orientation of the photo.  This is most frequently encountered with photographic images taken with digital cameras.
Most modern web browsers and operating systems ignore this metadata, but certain operating systems [such as Mac OS and iOS] are known to utilize some of this metadata to determine how an image should be displayed on web page.  
As one example, an image that displays as-desired in current browsers on a Windows workstation may display as rotated a quarter-turn in one direction when viewed on an iPhone.

To resolve this issue:
  1. Create a copy of the image and save it without the metadata
  2. Upload the new image (without the metadata) to the image library
  3. Replace the problematic image with the new copy in the corresponding design or part
Most of this type of digital photo metadata can be effectively removed by saving a copy of the image as a .jpg/.jpeg file from a simplified image editing tool, such as Microsoft Paint.  
For detailed information about removing metadata from a specific image file, please contact the professional service provider or software vendor who provided the image file or the tool with which the image file was created, as detailed editing of image file formats is beyond Blackbaud's scope of support.