FAQ.File problems
When uploading a file - this file does not open.
Most likely the problem is that the files are not uploaded as binary objects, but as text objects. To check, compare the size of the file BEFORE and AFTER uploading. Also try downloading the file back to your computer and trying to open it. To solve this situation - you need to change "CharsetRecodeMultipartForms" parameter in Apache web-server configuration.
Search the Internet for information on the "CharsetRecodeMultipartForms" operator