Method: ActionView::Helpers::AssetTagHelper#image_tag

Defined in:
actionview/lib/action_view/helpers/asset_tag_helper.rb

#image_tag(source, options = {}) ⇒ Object

Returns an HTML image tag for the source. The source can be a full path, a file, or an Active Storage attachment.

Options

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

  • :size - Supplied as "#{width}x#{height}" or "#{number}", so "30x45" becomes width="30" height="45", and "50" becomes width="50" height="50". :size will be ignored if the value is not in the correct format.

  • :srcset - If supplied as a hash or array of [source, descriptor] pairs, each image path will be expanded before the list is formatted as a string.

Examples

Assets (images that are part of your app):

image_tag("icon")
# => <img src="/assets/icon" />
image_tag("icon.png")
# => <img src="/assets/icon.png" />
image_tag("icon.png", size: "16x10", alt: "Edit Entry")
# => <img src="/assets/icon.png" width="16" height="10" alt="Edit Entry" />
image_tag("/icons/icon.gif", size: "16")
# => <img src="/icons/icon.gif" width="16" height="16" />
image_tag("/icons/icon.gif", height: '32', width: '32')
# => <img height="32" src="/icons/icon.gif" width="32" />
image_tag("/icons/icon.gif", class: "menu_icon")
# => <img class="menu_icon" src="/icons/icon.gif" />
image_tag("/icons/icon.gif", data: { title: 'Rails Application' })
# => <img data-title="Rails Application" src="/icons/icon.gif" />
image_tag("icon.png", srcset: { "icon_2x.png" => "2x", "icon_4x.png" => "4x" })
# => <img src="/assets/icon.png" srcset="/assets/icon_2x.png 2x, /assets/icon_4x.png 4x">
image_tag("pic.jpg", srcset: [["pic_1024.jpg", "1024w"], ["pic_1980.jpg", "1980w"]], sizes: "100vw")
# => <img src="/assets/pic.jpg" srcset="/assets/pic_1024.jpg 1024w, /assets/pic_1980.jpg 1980w" sizes="100vw">

Active Storage blobs (images that are uploaded by the users of your app):

image_tag(user.avatar)
# => <img src="/rails/active_storage/blobs/.../tiger.jpg" />
image_tag(user.avatar.variant(resize_to_limit: [100, 100]))
# => <img src="/rails/active_storage/representations/.../tiger.jpg" />
image_tag(user.avatar.variant(resize_to_limit: [100, 100]), size: '100')
# => <img width="100" height="100" src="/rails/active_storage/representations/.../tiger.jpg" />



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# File 'actionview/lib/action_view/helpers/asset_tag_helper.rb', line 430

def image_tag(source, options = {})
  options = options.symbolize_keys
  check_for_image_tag_errors(options)
  skip_pipeline = options.delete(:skip_pipeline)

  options[:src] = resolve_asset_source("image", source, skip_pipeline)

  if options[:srcset] && !options[:srcset].is_a?(String)
    options[:srcset] = options[:srcset].map do |src_path, size|
      src_path = path_to_image(src_path, skip_pipeline: skip_pipeline)
      "#{src_path} #{size}"
    end.join(", ")
  end

  options[:width], options[:height] = extract_dimensions(options.delete(:size)) if options[:size]

  options[:loading] ||= image_loading if image_loading
  options[:decoding] ||= image_decoding if image_decoding

  tag("img", options)
end