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Video files, audio files, text files, pdf files, microsoft word files will be uploaded and associated with a standard thumbnail. All other types will be uploaded and have the thumbnail "Preview not available"
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text files: .ics, .ifb, .css, .html, .htm, .asc, .txt, .rtx, .rtf, .sgml, .sgm, .tsv, .wml, .wmls, .etx, .docpdf files: .pdf