Change an image with JS after it has been loaded with angular?

I'm trying to do a chrome "snippet" to change the images of a page created with angle.

I am trying unsuccessfully with:

this.src=origen+res[res.length-1];
this.setAttribute("ng-src",origen+res[res.length-1])

But by not acting on the "real" DOM but one already processed by angular does not update the image. Is there any way to do it once the web has been loaded and from an external JS, such as snippets or extensions?

Go ahead that I not only know angularly superficially, thank you