Right click somewhere in the table, and then click on "Table Cell Properties."  The dialog box you get will be somewhat self explanatory.  A litttle extra help:  "Cell padding" is space between the edges of the cell and the words (or graphics).  The height of a table or cell will stretch to whatever you put in the cell, but you can force cell height to something larger by specifying some large number of pixels.

Netscape v. 4.7 allows you specify a background image within a table or cell within a table: v. 7 does not allow this somewhat useful feature.  (It can be used to put text over an image without writing the text on with a image-processing software--you specify the cell size to be the image size, then use the image as background of the cell and write over it with ordinary text.  However, the viewer can set the font size of your prose so large that it will force the cell size to be larger than your picture.  The picture will then be repeated -- as is the starry background of this page.

This is an important lesson.  When we design web pages, we must consider that browsers let the viewer make a lot of adjustments: font size, turning off graphics, colors of links, etc.   What we put into the page may not show up as we expected.

As web page code--and browsers that interpret it--get more and more elaborate, older features are dropped out of what's permissible.