Adding Attachment Types 
Path to adding new extensions: Attachments > Attachment Manager, and click the click the Add New Attachment button at the bottom of the screen.

Following is the Add New Attachment form of the Attachment Manager.

<<<Insert a screenshot of the Add New Attachment form of the Attachment Manager.>>>

The following are the options you can set in the Add New Extension form.
Note:
You must click Save for changes to take effect.
Extension
Extension of the allowed file type.

Example: jpg, in lowercase letters without the leading period (.).

Max Filesize (in bytes)
Maximum filesize for individual attached files of this extension.

Take your overall site storage limitations into consideration in deciding what size files to allow. You also need to consider the MySQL and PHP settings that affect the maximum file size you can upload.

Generally one megabyte is a good rule of thumb. If you need larger files and find yourself not able to post them, you'll need to ask for support via our ticket system or on the support forums.

Maximum Width (in pixels)
Maximum width of an uploaded image. This setting applies only to some image types. By default we include all image types that support this option.

This only applies to image files of the extensions: bmp, gif, jpe, jpg, jpeg, png, psd, tif and tiff.

Maximum Height (in pixels)
Maximum height of an uploaded image. This setting applies only to some image types. By default we include all image types that support this option.

This only applies to image files of the extensions: bmp, gif, jpe, jpg, jpeg, png, psd, tif and tiff.

Mime Type
The mime type dictates how the browser handles the files when the attachment is opened. General mime-type lists are available on the Internet.

If you leave this option blank, the user’s browser will probably prompt for save.

Content Type
This section gives you the option of adding the extension to specific parts of the your vBulletin. The columns are as follows:

Product - the name of the product that users can add an attachment with the named extension

Location - the location where that users can add an attachment with the named extension

New Window - whether or not the attachment is opened in a new windows.

Enabled (Yes/No)
Controls whether or not this attachment type is allowed to be uploaded.
User Contributed Notes: Adding Attachment Types