Yeah what others have said, really. They need to be simple and clear. Lose the clothes, hair and maybe skin texture (for body images) for any promos show casing the morphs, other wise your morphs get a bit lost with everything else that's going on.
You need strong lighting, Im pretty sure the image above will be much too dark for Daz's taste.
Also avoid crowded images with more than 2 figures.
I've had my early promos rejected in the past because of these ^
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