As discussed: this is probably as easy as mangling the image urls to use image://thumbnailer/ either for all non-image:// ones or at least for a whitelist of {http,https,file,ftp} ones.
As discussed: this is probably as easy as mangling the image urls to use image:/ /thumbnailer/ either for all non-image:// ones or at least for a whitelist of {http,https, file,ftp} ones.