I have tried to photograph an 20 seconds AVI format movie of a reignition of a HPS lamp in a floodlight, using the lowest resolution available in my camera (320x240) and the size of the movie that producted was 6.5MB, very large for its resolution and its time length. What the movie was so large for its time length? Is the digital zoom (Which was at maximum) and the soundtrack contributs to the size of the movie file?

yeah, because that's the max file size, use somewhere else to upload the file, if movies where allowed here the space would fill up FAST!

You are not answered my question in the post! Read it until the end.

AVI is no exact video format, the file size depend on the real video format used (MPEG-2, MPEG4, DIVX,...). When preparing the file in PC, it depend on codec setting in your editing SW.

Well, I'd love to help, but even the webmaster said it wasn't possible due to space, so maybe be a little nicer to the members and maybe you will get more help!

Movies cannot be uploaded into the site, regardless of their size.  This site only hosts still photos, not motion pictures.  If you want to upload a still photo, and then provide a link to the movie that is uploaded into a movie-hosting site (i.e.: You Tube), that's fine.

Technically, the site will allow you to upload very small videos (less than 2MB).  Although we have ample disk space for now, it could be filled up fast if we allowed large videos.  Also, our site will not transcode video files for you.  If your video is not already encoded in a format supported by common browser plugins, members will have trouble viewing it.  If you'd prefer to put a video in the gallery rather than on the message board but it is too large to upload, simply upload a still frame and link to the video in the description.