Thumbnails are automatically generated when resource files are uploaded to TES. They display the first page of a resource file e.g. the first page of a word doc. These thumbnails appear in search results on the site and within resource pages.
Please note the following file types will not appear as thumbnails:
All video file types (MP4, FLV, AVI, WMV, 3GP, SWF)
All audio file types (WAV, MP3, AIFF, FLAC, RAW)
Microsoft Publisher (PUB)
Microsoft Excel (XML, XLSX, XLSM, XLSX)
Tarsia files (FJSW)
Smartboard (NOTEBOOK, XBK)