1. File Extension Mini-Lesson
Computer Applications
File Extension Mini-Lesson

2. Photos
.jpg (most common)
.gif (graphical interchange file)
.png (portable network graphic)
.tif (tagged image file)
.img (image)
.bmp (bitmap)
Why it matters:
File size
Resolution
What software will open it

3. Video
.mpg (movie picture experts group)
.avi (audio visual interleave)
.wmv (windows media video)
.flv (flash video)
Why it matters:
Size
What software will play it
If ‘codecs’ are needed to decode it

4. Documents
.doc (Word 2003 or older)
.docx Word 2007 or newer)
.rtf (rich text format)
.txt (text only)
.pdf (portable data file = Adobe Acrobat)
Why it matters:
- What software will open it

5. Music
.mp3
.cda
.wma
Why it matters:
- Which devices will play it

6. Other
.xls (Excel 2003 or older)
.xlsx (Excel 2007 or newer)
.ppt (PowerPoint 2003 or older)
.pptx (PowerPoint 2007 or newer)
.htm (hypertext markup language)
.html (hypertext markup language)
.exe (executable…DANGEROUS if you don’t know what it is!)
.msi (Microsoft installation file…DANGEROUS if you don’t know what it is!)

7. Converting Files
Some programs like Prism will convert files from one format to another.
Some web-based programs like zamzar.com will also convert the file and you a link to it.

8. Review
Name two kinds of photo file extension
Name two kinds of video file extension
What kind of file is one that ends in “.ppt”?
What kind of software would I need to run a “.xlsx” file?
Which file extension is used on iPods?
Can files be converted from one format to another?
What website could one visit to convert a file?