It is very painful to use this awesome editor without being able to insert image easily and color the Visual Editor cells
Topic on VisualEditor/Feedback
You can insert images into table cells. Click in the cell, as if you are going to type words, and then choose Insert > Media. You will probably want to use the "advanced" features to change the formatting of the image.
Coloring (lines, backgrounds, text) is unfortunately not an option right now.