vBulletin Manual - Image Settings

The vBulletin Options > vBulletin Options > Image Settings setting group allows you to control how vBulletin processes images for uploading and handles image verification.

Image Processing Library
vBulletin provides two options for manipulating attachment thumbnails, custom avatars, and profile pictures.

The first is GD, which is bundled with PHP 4.3.0 and later. GD supports the following file types: GIF, JPEG, and PNG.

The second supported library is ImageMagick v6 by ImageMagick Studio LLC. ImageMagick is an executable binary that must be installed at the server level to be called by PHP. Only the identify and convert binaries from ImageMagick are required by vBulletin. ImageMagick supports the following file types: GIF, JPEG, PNG, BMP, TIFF, and PSD. ImageMagick also has better support for handling animated GIF.
Image Verification Library
This is similar to the option above but it chooses the Image Manipulation Library for inline image verification. These verification images can be enabled for registration and the Contact Us forms. There are two options for GD. The first, "GD (Simple Font)" will use an internal GD font. The second, "GD (True Type Font)" will use the fonts located in the images/regimage/fonts directory of your forum. On some PHP installations the TTF font option will not work. If you have the TTF font option selected and are seeing no fonts, try the Simple Font option.
Image Verification Options
There are several options that allow you to control the level of difficulty presented by the image verification.
ImageMagick Binary Path
Path to the ImageMagick 6 binaries (convert and identify). Example:
Unix: /usr/local/bin/
Windows: C:\imagemagick\

When you are done, click the [Save] button to apply the changes.