Thx m8, you have been a huge help. Much appreciated.

I'm not sure if I should try doing it with a function like your code or use the php function parse_url() to do all the work.

I'm guessing you proxy all images even if they are already https as I dont see anything that looks for a https match or specifys the function only for http images.

That's correct. I proxy all images. So I don't have to deal with image not found when the image finally gets deleted from the host.

Besides proxying all external images, my function also anonymizes non image urls. So every external url passes through that function.

Btw, "i' in regex/preg_match make the regex case-insensitive.