My image turns into this "\" when I save my change

I am having a problem.

ex. when I edit a file, the file structure is as follows:

document.write('<div><img name="defaultslide'+this.slideshowid+'" src="'+this.postimages[0].src+'"></div>')

Then when I view the source on the actual page, it changes to this:

document.write('<div><img name="defaultslide'+this.slideshowid+'" src="/'+this.postimages[0].src+'"></div>')

any ideas?