what kind of specs should my stills have (either scanned images/images from the internet/ or images from photoshop) when importing them to an HD timeline.
The HD timeline is 1440*1080
pixel aspect ratio = 1.3333 (HDV 1080)
you can use 1440*1080, pixel aspect ratio 1.3333. To view correctly in Photoshop, pick "View -> Pixel Aspect Ratio -> HDV 1080 ... (1.33)" and activate the "Pixel Aspect Ratio Correction" in case it's not already activated.
However, 1920*1080, pixel aspect ratio "Square" will work as well in a 1440*1080, 1.3333 project.