[request feedback] removed magic constant; GirlsOfDesire ripper works except for server 403

I cloned EHentai ripper into GirlsOfDesire ripper, and managed to get everything to work EXCEPT it seems that some magic on the server side is preventing the client from accessing image files which haven't first been loaded from the specific website, and I'm getting 403's on these otherwise valid URLs.

I wonder if you could have a look at this and see what maybe needs to be changed to get it to work?