So you have autotraced some photos and now you want to export them as raster files again? Why?
I've traced the images because I need them larger.
By tracing them I also gave an illustration look.
The fact is that for production I need a Jpg at 300dpi and my setup is not able to do it directly from Illustrator.
Your problem is antialiasing.
You could try a different setting in Illustrator's Image Trace and maybe then it will look better when importing in Photoshop.
Set the Method to "Overlapping" in the Extended options