Free Transform Tool help

Hi All

Im sure im doing somthing wrong but cant seem to sus it out so any help will be great.

What i have are some pictures on my stage, now i want to rotate them each by about 30 degrees but when using the free transform tool no matter what i do when i rotate them i cant get the lines to stay nice and crisp they are all jagged and looks horrible am i using the wrong tool for the job or do i need to adjust the settings as i just cant sort it out. The pictures are jpg’s imported to the library then changed the image settings to 100% quality, should i be using a different image format as i do have an imported psd image and i have tried it with that and still get the same.

thanks in advance