To import an image (especially a complicated one) onto a PCB (in Altium) you're going to have to do some work. There is also an official Altium Video explaining this process. This approach works best if you put your logo into a PCB library, so you can simply place it on any PCB and edit it at a central location. Group your regions by selecting them and creating a union from them (Tools>Convert>Create Union from selected objects).You can delete all regions that should not be filled, as well as your original DXF lines. Now your polygon consists of several copper regions.Repour the polygon, then select it, right click on it and use Polygon Actions>Explode selected Polygons to Free Primitives.Adjust the clearance for the polygon to the DXF lines to 0 by adding a specific design rule.Set small values for neck width and arc approximation. Draw a polygon pour around the shape (Place>Polygon pour), select pour over same net objects and disable removal of Islands.Use the Inspector panel to set the line width of the DXF geometry to a very small value, e.g.Import your dxf file (File>Import>DXF).The procedure of creating a 'solid' logo from the DXF lines is a bit lengthy, but very reliable and gives high quality results. Might not work well with pictures, but since most Logos also come in 'simplified' vector forms, it might still be an option. If you have your logo in vector form, you should export it as dxf which Altium can import.

Pcb logo creator for altium 17.0 download