How can I get rid of the content edges when I mask it with smaller container in Illustrator?

I have placed an image about 1000px*800px and I mask it with a box of 500px*500px now the content boundaries of the image is annoying me when positioning with smart guide and align it. it always align and keep track to the bigger content not the small mask.

my question is: how to get rid of the edges of the content without turning the global edges off?