What type of images are displayed directly within a web page?

Inline images are the correct choice because they are specifically designed to be embedded directly within the content of a web page. This means that when you view a web page, inline images appear as part of the HTML layout, positioned alongside text or other elements. They enhance the visual presentation of the content and often load with the rest of the web page, making them integral to the user's experience.

Background images, while important for visual design, are typically set in CSS and occupy the background of elements rather than being part of the content flow. Raster images refer to a format of images, such as PNG or JPEG, but do not indicate how they are displayed on a web page. Thumbnail images are generally smaller representations of larger images, often used as previews, and are not inherently tied to the concept of inline display. Thus, inline images are pragmatically the most relevant category for images being shown directly in a webpage's content.