Save image & keep structure in PHP

Im currently working on a way to archive webpages using PHP. What I am currently stumped with is the a way on how I can save images from the page and keep the same folder structure.

So far I have extracted the URL to the image. What im left with is:
www.testsite.com/img/main/layout/head_image_cc_09.jpg
what I need to do now is copy that image to my server and still have the correct file structure.
for example I want it to be like this:
copy testsite.com/img/main/layout/head_image_cc_09.jpg
to www.mysite.com/archive/testsite.com/img/main/layout/head_image_cc_09.jpg

Any ideas?

EDIT: Maybe to make it a bit easier, maybe even a way to remove everything before the filename and the file extension. So like change 'testsite.com/img/main/layout/head_image_cc_09.jpg' to just head_image_cc_09.jpg. I would actually though have to be able to remove the filename and not just get image properties. Like remove all characters before and including the / symbol.

I would really really much prefer the first idea, but if thats not plausible then I guess the second way should be alright, but would require much more work.