A very brief overview of how to add images to your post excerpts.
Previewing another WordPress blog
A post with a left-aligned image
Images don’t need to fill the full width of your content column. You can have smaller icons or photos that appear, and you can align these to either side of the column. This example shows a left-aligned image (in case you forgot your right from left). And here follows some beautiful dummy text to pad [...]
A post with a right-aligned image
Like I mentioned in another post, you can make use of images that don’t fit the full column width, then have the text wrap around by setting the alignment (left or right).