you select the inserted CAD photo, right-click, then select "format object", and set the line drop-down box to "no pure line color" in the "color and practice line" page of the dialog box.
the method of displaying and hiding border lines in p>CAD is as follows: create a layer named hidden line in the layer properties manager, go back to the view and select the border line, find the hidden line layer in the layer bar, and click it, so that the border line is in the hidden line layer. Turn off the hidden line layer and the border line will not be displayed.