Images appear in landscape orientation instead of portrait.
This is a bug in Apple Mail unrelated to Attachment Tamer. Modern cameras and image editing software often store information about orientation separately from the image data itself in a so-called EXIF section. Certain applications including most web browsers and Apple Mail ignore EXIF orientation.
Workaround: Unless you use Mail to resize the image (more on how to prevent unwanted resizing), the EXIF information is preserved, and the recipient will be able to view the image in the correct orientation using EXIF-aware software. Likewise if it is in a message you have received, the information is there in the image file, just open it in the Preview application.