> I'd like to see a new feature in HTTrack, and which 
> shouldn't be difficult to develop. Would it be possible 
to 
> set up a minimal size for filter some types of files ? 
eg, 
> if I want download only images > 10 KB.

This already exists, but because the test can only be made 
AFTER files are being downloaded (and links are being 
written), this will cause broken images or broken links.

Anyway, you can use in 'Set Options'/'Scan rules' syntax 
like:
-*.gif*[<10]
To exclude all gif files smaller than 10KiB

or
-*.gif*[<10>1000]
To exclude all gif files smaller than 10KiB or bigger than 
1000KiB

> When I download web sites with big files, theey are often 
> incomplete, and when I want to finish to download the 
site, 
> HTTrack see them as downloaded, so doesn't complete 
them...

This might be due to two different causes:
- The remote server is not able to fullfill to update 
requests sent by httrack
- The connection related to those files are closed suddenly 
without proper size information sent by the remote server 
("streamed" files) - there is no way to detect the problem, 
unfortunately