Colors on my image keep inverting after I save

[tasmith7]

I'm new to the forum and definitely not a Cad guru. Just know enough to be dangerous. I have an image that I've inserted that I need to create vector polylines and delete existing text. I have the image where the background color is black and the contours, text, etc. in the image are white. Once I start deleting the existing text and creating polylines from the contours on the image and then try to save, the colors get inverted so that the background is white and I can barely see the contours and text within the image. I'm sure that is clear as mud, but any help would be appreciated.

Thanks,
Adam