ولا مصور أي ذي صورة وشكل
Nor does He possess an image, form or shape.
Form and shape describe the arrangement, surfaces and boundaries of a physical body. A person and a horse have different shapes, but in both cases there is a determinate bodily configuration.
To ascribe shape to God would imply constituent parts, measurable structure and selection of one configuration rather than another. Each of these brings the question of what determines that configuration, implying contingency rather than necessary, independent existence.
Contrast: A triangle is properly described by its three sides. Applying triangular—or any other—shape to God would confuse the Creator with a configured body.