I only tested the code from the documentation (exactly as written above). And 'this_page.html' and all files will be placed in the working directory. I can change target_file location and save somewehere else but whatever location I use for target_dir, all files are always saved in the working directory.
I am still using WWW::Mechanize::Firefox and would like to migrate to Chrome. Just for your information, I was not able to install WWW::Mechanize::Chrome with ActiveState Perl running despite your advice to force the installation of Imager::File::PNG if screenshots are not necessary. I tried to force the installation of Imager::File::PNG as well as WWW::Mechanize::Chrome using cpanm but it did not work. Now I am using Strawberry Perl