This depends on the context. In some contexts, images are only used to enhance the look and feel of a web page. For example, some web pages use bitmap to draw the border of tables. Such use of images is not necessary. If the web page is to be more accessible, the use of these images should be kept at a minimum. We can refer to these images as contentless images, as their absence does not affect the content delivery of the web page.
On the other hand, pictures of products or well recognized icons can help visual-oriented users find information and links more efficiently. In this case, the absence of images makes the web page less accessible to those who are more visual-oriented. As such, these images are necessary.
As a long-term strategy, a web page should be dynamically generated based on the same content. This permits the use of one presentation that is plain text only for accessibility, while another presentation is more for visual-oriented users.