Plugin no longer working on server transfer

I have a website which utilises the Supersized plugin and it was correctly there. When I have transferred the website in exactly the same fashion as many other sites before (from the same host to the same new host), the plugin stops working.

I wrote to the new host and they said: I’ve seen that some of the plugins which perform the ‘supersize’ functions do so by calling the file again from it’s current location but altering the size. This would possibly entail a ‘loopback’ connection and these are disabled on our servers by default.

Is this what could be going on here? Is there an alternate configuration which I could use?

http://ww.wp.xz.cn/extend/plugins/wp-supersized/