Background: Correct me if I am wrong. TV's use rectangular pixels. Computer monitors use square pixels. So, say you create an image/title in photoshop and want to add that to DV footage. My understanding is that the image/title you create has to be created in a different resolution. Preferably higher because when added to DV footage, the resolution will be downsampled to support the rectangular pixels in DV footage (this is so no distortion will take place).

Question: What frame size do the square-pixel images have to be so that there is no distortion when added to DV footage? Now, I've gone through the Adobe Premiere help files and they say 720x540 or 640x480. Preferably the former to prevent upsampling (resolution loss). Oh, this is also if DV is in NTSC.

I just want to verify my question. I've actually tried this in Adobe Premiere but using DV(NTSC) widescreen footage. And it looked distorted to me. Maybe it's different in widescreen?

The Meyers book on Creating Motion Graphics has a whole chapter devoted to this issue re After Effects, but it would apply equally to Premiere I think.

Some programs allow you to set the pixel aspect (most 3D
apps do for example). I don't know if Photoshop offers such
a thing though. Perhaps resampling might be in order for
your pictures, and yes, you want to go from a higher resolution
to a lower one, not the otherway around....

When you import footage to the Premiere timeline then
right-click on it, Advanced Options -> Pixel Aspect Ratio
you can change your sources pixel aspect. Make sure
you have set Maintain Aspect Ration under Video Options
in the same popup menu! This will interpret your footage
in the correct way.

Premiere tells me that these are the aspect ratios for
PAL & NTSC... normal / anamorphic (16:9)

PAL 1.067 / 1.422
NTSC 0.9 / 1.2

With these numbers you can calculate what the picture
size in Photoshop must be for correct import in Premiere.
Fiddle around with it.