I'm downloading a linux image here, its size is
But the browser always finishes downloading at only
This kind of thing doesn't happen if I use a dedicated tool for downloading,
why it's so weak in browser?
The problem is that your internet connection must be dying out in between. Most browsers can't handle resuming downloads well and hence your download dies out. Using a download manager will help you resume. If you are behind a proxy server, you might face such problems too.