TRichView.com

How to insert a picture that it was behind the text?

Only using table with background image.
Or, On page, you can draw an image yourself (RVPrint.OnPagePrepaint event)

And how to make a transparent background of the table?

If you mean images with transparent areas, use image formats supporting transparency (gif/png/metafile).
Table.Color, and Color of cells must be equal to clNone for a transparency.

thanks a lot!