If you are using the "Free Transform" tool in photoshop to rotate the image, I found that rotating and scaling in the same "Free transform" session causes more

If you are using the "Free Transform" tool in photoshop to rotate the image, I found that rotating and scaling in the same "Free transform" session causes more jagged edges. Doing the rotate first, then doing the scale looked better. Not sure if you are doind that anyway, but the edges of your image looked like mine when i was :)