'Advanced' Computer Course for Seniors
presented by Paul and Myrna Goyetche
Files Types or format


Your computer can handle all types of files. Each program on a computer can only handle certain format of files, therefore it is very important for your computer to know what format each file is in. The file format used to be called file extension. For example, a picture coming out of a camera usually has a file type of jpeg which is the acronym for Joint Photographic Experts Group. Therefore a picture file could look like IMG_0001.jpg . Depending on the make of your camera, the file names differ but will always be followed by the 'extension' .jpg.

In Explorer, choosing a file will usually automatically open the file with the appropriate software. Below is a list of the top file formats you should see.

Adobe Flash (.swf)
Adobe Portable Document Format (.pdf)
Webpages (.htm, .html,)
Microsoft Excel (.xls, .xlsx)
Microsoft PowerPoint (.ppt, .pptx)
Microsoft Word (.doc, .docx)
OpenOffice presentation (.odp)
OpenOffice spreadsheet (.ods)
OpenOffice text (.odt)
Rich Text Format (.rtf, .wri)
Text (.txt, .text)
XML (.xml)
Music (.mp3, .wma, .wav, .aac)
Pictures (.jpg, .bmp, .raw, .gif)
Videos (.mov, .avi, .mpg, .mp4)
Emails (.eml)
Compressed Folder (.zip)

There are hundreds of others but we will be concentrating on the above. For a full list of file formats, click here.

Determining which program will start when a certain file is open is called File Association or default program settings. Go get here choose Start>Default Programs. The screen below should appear:

The second option is the associate function. When choosing this, you can see which progams will open which file formats. See below.


The other way to change the program associated with a file format is the Open with... options. When you right click on a file, you may have the option of opening it with more than one program. There you have to option of using the Choose Default Program at the bottom of the menu.

Remember, right clicking the mouse on objects gives you all the choices you can do with that object.

Attachments in e-mails
When you receive an attachment in an e-mail, it will probably contain one or more files of the formats above. If you are getting a message that you cannot open it, it may be because your file association is wrong or that you just don't have the software on your computer to open the file. If you do have the software and specify open attachment, it will launch the appropriate program. Very Important: The attachment you open in a e-mail is in a temporary place on you computer. If you ever want to see it again or even change it, you should save it to a 'permanent; place in your documents. Doing a Save, will simply save it in a temporary file system that could get deleted at any time. You must use the Save as function and save it to one of your directories where you will be able to retrieve it later.

Email limitations
Depending on which e-mail system you use, there are file size limitations into what you attach. For example, sending a video through e-mail could overload your e-mail or the recipients. Also, you could easily reach these limits by sending many pictures in an e-mail. In Yahoo mail for example, the limit you can send in single e-mail is 25mb's. This represents about 10 pictures with a high resolution.

In computers, size is important. Click here to continue to the File Size section.

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