> It's possible to download picture from a site
> without Httrack making the structure?Only if you know the urls of the files
or know the url of the directory and that's not protected.

> That don't work with picture downloader software
> because I want to download parts of zoomed picture.
What software? Always give the url you're trying, the version and options. We
are not mind readers.

> Httrack make a structure for all possibility to zoom
> into the picture, so after download I have, for
> example, 400 html file to do the structure for only
> 50 pictures I want.
Without the html, you may not know what order the images go.
Are all the html part of the pictures, if not you filter out rest.
 
> It's seem to me that Httrack take a long time to do
> this big structure during download. But maybe I'm
> wrong for that and it's just the scanning that take
> a long time.
Scanning html is quick.  Perhaps you overloaded the site and triggered denial
of service delays.