Here's how I do it:
1. First, I create a one-cell table format with title. Name it whatever
you want, perhaps Graphic. I place the graphic in the table cell and the
caption in the table title position, which can be set above or below the
table (graphic). Or turn off the title if no caption. In the Table
Designer, on the Basic tab, set Spacing Above to -2.0 pt.
2. Create an anchor paragraph style to hold the table, perhaps naming it
TableAnchor. In the Paragraph Designer, on the Basic tab, set Spacing
Below Pgf to -2.0 pt for this paragraph style and select the "Fixed"
checkbox. On the Default Font tab, set the font to 2.0 pt. NOTE: This
number can be any number you want, as long as you use the same number
(but negative) in the other two places I mentioned.
Now, to place your graphic, first create an empty TableAnchor paragraph
in your document. Insert a new table into the paragraph using your new
Graphic table style. Place your graphic in the table cell and shrinkwrap
it (Esc m p). Place your caption in the table title. Everything will sit
flush with the top of the page column.