Yes – 55 words. But you can use the Optional Excerpt within the Edit Post page to create your own custom excerpt using as many (or as few) words as you like. There are also a few plugins out there that help with customising the excerpt.
Or, you could use the more tag and just not put any images above it.
Or, you could use CSS’s display: none to hide images on the homepage. You’d have to add a CSS class or id to the post content in index.php and then reference img in that class/id. Not sure if you could use inline CSS to do that.