Files
You should not mistake "files" for "pages": While a (web-) page is a HTML document shown natively by any web-browser, files are documents in other formats that browsers usually do not show but download. (Most browsers nowadays seem to show PDF files immediately, but that's not really true: In fact, they download the file and display it in a PDF viewer program that is "plugged-in" into the browser.)
The following types of documents might be useful to be offered as files (for download):
- PDF files
- Images
- ZIP-files of entire folders containing several documents
- MS Word, Excel, Powerpoint and other (?) documents*
*If you do not want that other people might be able to change your documents once they downloaded them, you'd better not offer them in the original MS format but rather as PDFs. But if you, for instance, want to offer a file like a form that users should fill with their information, than you may use .doc and its colleagues - but modern PDF viewers also allow you to use PDFs as forms while - at the same time - they do not allow the user to change those parts of the document that should stay unchanged.
Before you upload any file make sure that you checked any possibilities to make it smaller, like
- packing it with a zip-program or
- resizing images to the maximum resolution needed (as long as the images should not be delivered in high-quality printing format, a size reduction to 600-800 pixels width should be sufficient)
- taking colours off the images, i.e. giving them in black/white or grayscale instead of full colour
- etc.

