It gives you cookies Sin puntuar aún

I have my browser set up to reject all cookies accept for exceptions that I have allowed and some how this addon is still able to give me cookies even after I try to block with exceptions.
You do not need this application in order to download images, videos, sounds, from websites all you have to do is type in your browser about:cache and click on the top one or bottom one that says "list cache entries" then search for a file format that you are looking for and it should almost always have the same domain as the domain name that you are at that you want to download the file for example just press ctrl+f then type in jpg, jpeg, gif, png...etc if you are looking for an image or for video you would type flv, wmv, mov... etc or for audio type mp3, wma...etc and then press enter keep searching once you have found something that you think might be it then click on it then click on it again and a window should pop up asking you if you want to download it.

Esta valoración es de una versión anterior del complemento (2.6.1). 

Re: It gives you cookies

The extension installs one cookie whose value is the number of downloads you achieved. It is used to show you this count in the website.

This is described at http://www.downloadhelper.net/faq.php#download-counter

You can disable this cookie from the preferences.

But please, keep going with your about:cache method ;)