Bring image to front/Send to back

Hi,

I use a lot of images whilst doing my drawings. I cant figure out how to send an image to back or bring my drawings to front.

I have done what I usually did with AutoCAD which is highlight the Image and click send to back but even that doesn't seem to work I just end up with the occasional line showing above the drawing and the rest behind.

Does anybody have any suggestions to where i might be going wrong?

Thanks

Dawn