How to create files of any size
fsutil file createnew C:\Brij\One_MB_File.doc 1024000
Above command will create 1 MB file called "One_MB_File.doc" at C:\Brij location.
You can provide any file extension - e.g. .txt, .xls, .ppt, .pdf etc.
This command may help in creating files for upload/download test in SharePoint or any other application.