method

image_tag

v3.2.13 - Show latest stable - Class: ActionView::Helpers::AssetTagHelper

image_tag(source, options = {})

public

Returns an html image tag for the source. The source can be a full path or a file that exists in your public images directory.

Options

You can add HTML attributes using the options. The options supports three additional keys for convenience and conformance:

:alt - If no alt text is given, the file name part of the source is used (capitalized and without the extension)
:size - Supplied as “{Width}x{Height}”, so “30x45” becomes width=“30” and height=“45”. :size will be ignored if the value is not in the correct format.
:mouseover - Set an alternate image to be used when the onmouseover event is fired, and sets the original image to be replaced onmouseout. This can be used to implement an easy image toggle that fires on onmouseover.

Examples

image_tag("icon")  # =>
  <img src="/images/icon" alt="Icon" />
image_tag("icon.png")  # =>
  <img src="/images/icon.png" alt="Icon" />
image_tag("icon.png", :size => "16x10", :alt => "Edit Entry")  # =>
  <img src="/images/icon.png" width="16" height="10" alt="Edit Entry" />
image_tag("/icons/icon.gif", :size => "16x16")  # =>
  <img src="/icons/icon.gif" width="16" height="16" alt="Icon" />
image_tag("/icons/icon.gif", :height => '32', :width => '32') # =>
  <img alt="Icon" height="32" src="/icons/icon.gif" width="32" />
image_tag("/icons/icon.gif", :class => "menu_icon") # =>
  <img alt="Icon" class="menu_icon" src="/icons/icon.gif" />
image_tag("mouse.png", :mouseover => "/images/mouse_over.png") # =>
  <img src="/images/mouse.png" onmouseover="this.src='/images/mouse_over.png'" onmouseout="this.src='/images/mouse.png'" alt="Mouse" />
image_tag("mouse.png", :mouseover => image_path("mouse_over.png")) # =>
  <img src="/images/mouse.png" onmouseover="this.src='/images/mouse_over.png'" onmouseout="this.src='/images/mouse.png'" alt="Mouse" />

# File actionpack/lib/action_view/helpers/asset_tag_helper.rb, line 356
      def image_tag(source, options = {})
        options.symbolize_keys!

        src = options[:src] = path_to_image(source)

        unless src =~ /^(?:cid|data):/ || src.blank?
          options[:alt] = options.fetch(:alt){ image_alt(src) }
        end

        if size = options.delete(:size)
          options[:width], options[:height] = size.split("x") if size =~ %{^\d+x\d+$}
        end

        if mouseover = options.delete(:mouseover)
          options[:onmouseover] = "this.src='#{path_to_image(mouseover)}'"
          options[:onmouseout]  = "this.src='#{src}'"
        end

        tag("img", options)
      end

5Notes

Using a block with image_tag

hardbap · Sep 30, 20111 thank

HTML5 officially supports block-level elements in the anchor tag and Rails 3 allows you to pass a block to image_tag:

<%= image_tag(some_path) do %> <%= content_tag(:p, "Your link text here") <% end %>

watch out for urls with &

grosser · Jul 10, 2008

image_tag('x.com/aaa?a=1&b=2') = x.com/aaa?a=1&b=2

By images's sub dirctionary to img tag

RobinWu · Oct 31, 2008

=== image_tag("icons/edit.png") # => edit

Specify your own template

Ramon · Mar 10, 2010

You can specify you own template this way:

def notice
...
@template = "some_other_name.html.erb"
end

Typing mismatch

yeuem1vannam · Jun 26, 2013

This block if size = options.delete(:size) options[:width], options[:height] = size.split("x") if size =~ %{^\d+x\d+$} end has type mismatch %r{^\d+x\d+$}