chrisnorthwood

This plugin adds a form to your post screen that allows you to upload an image to go with your blog post. You can then use <code>the_article_image()</code> function in your theme to show the image whereever you want on your theme, at whatever size (dynamically rescaled and cached using ImageMagick so no dodgy browser rescaling or sending huge photos out).
An example of it in use is on http://www.nouse.co.uk/, where the photo alongside each post is attached, and then shown on the front page, and on the single page itself in the theme.

Article Photos

This plugin adds a form to your post screen that allows you to upload an image to go with your blog post. You can then use the_article_image() functio …

Pat Hawks

dirtysuds

Once activated, Gallery posts will have an excerpt that is a row of thumbnail images from that post, rather than some (often not descriptive) text. 
This excerpt should appear in your archive pages, and perhaps elsewhere, depending on your theme.
Note: The post must actually have the post type ‘Gallery’. It cannot just be a post with a gallery in it.

Gallery Excerpt

Replace the excerpt for posts with the post type 'Gallery' to a row of images from the post.

Article Photos vs Gallery Excerpt