Images work in server, doesn't work in build

I’m trying to display some images in a blog post. The images are in a folder called {year}-{month}-{date}-{title}. In my post I reference them with ![alt text]({year}-{month}-{date}-{title}/{image-name}).

If I run the server all is fine, when I build I can see the images in my index page, where I have a list of my recent posts, but in the post page the image links are broken.

This is my config file:

configure :development do
  activate :livereload
end

activate :blog do |blog|
  blog.layout = "post"
  blog.summary_length = 1500
end

activate :directory_indexes

set :markdown_engine, :redcarpet
set :markdown, :fenced_code_blocks => true, :smartypants => true

activate :syntax

activate :deploy do |deploy|
  deploy.method = :git
end

set :css_dir, 'stylesheets'

set :js_dir, 'javascripts'

set :images_dir, 'images'

configure :build do
  activate :minify_css
  activate :relative_assets
  set :relative_links, true
  activate :gzip
end