In addition to defining background colors you can also add background graphics to your tables. For example, you can insert a single large graphic behind a table like a "watermark", or you can tile a small graphic to create a repeating pattern or texture as a background for the table.
You can apply a background graphic to a single cell of a table by using a single-cell nested table (inserting one table inside another) and applying the background graphic to the nested table.
1.Click in the table and select Properties in the Table tab or right-click and select Table > Properties to display the Table Properties dialog.
2.In the Table Layout tab select the Background Picture option.
3.Click on and select the graphics file you want to use.
4.Select Tile to repeat the graphic in a pattern or Center to display the graphic only once, centering it on the center of the table.
Matching the size of graphics to your tables can be tricky with centered images. The most practical solution is to use graphics that have an edge the same color as the page or table background so that you don't have to line up precisely with the edge of the table.
Graphics are normally applied to the entire table. If you want to apply a graphic to a single cell or range of cells you can do this by inserting a nested table and applying the background graphic to the nested table.
Table Properties (Reference)
How table sizing works (Reference)