We have released a new plugin, Simple Matted Thumbnails. This provides a new format for thumbnails in addition to the two that come with WordPress.

Thumbnail Formats

Proportional

This is the default.  The image is resized to fit in the box, the resulting thumbnails will vary on size if images with different aspect ratios are used.

Cropped

This is a choice available from the media settings for the thumbnails and in the settings of many e-commerce plugins.  The image is cropped to the exact size requested, care must be taken in preparing images to avoid losing important content.

Matted

This is the new format provided by this plugin.  The image is resized proportionally to fit in the box and then matted out to the size requested for the thumbnail.  The mat is similar to those used to frame photographs and watercolours.  This plugin lets you choose the colour of the mat and add extra matting around the thumbnail image.

Matted with extra matting

This adds a percentage of background colour around the image.

Where to Get The Plugin

The plugin is available from the WordPress Plugin Repository at http://wordpress.org/plugins/simple-matted-thumbnails/ and using the Plugins menu in the WordPress admin.  Please let me know of any issues using this plugin and any enhancements that you would like to see.