diff --git a/lib/philomena/duplicate_reports.ex b/lib/philomena/duplicate_reports.ex
index 4c8332d3..ec3a05e5 100644
--- a/lib/philomena/duplicate_reports.ex
+++ b/lib/philomena/duplicate_reports.ex
@@ -30,7 +30,7 @@ defmodule Philomena.DuplicateReports do
       where: it.ne >= ^(intensities.ne - dist) and it.ne <= ^(intensities.ne + dist),
       where: it.sw >= ^(intensities.sw - dist) and it.sw <= ^(intensities.sw + dist),
       where: it.se >= ^(intensities.se - dist) and it.se <= ^(intensities.se + dist),
-      where: i.image_aspect_ratio >= ^(aspect_ratio - aspect_dist) and i.image_aspect_ratio >= ^(aspect_ratio + aspect_dist),
+      where: i.image_aspect_ratio >= ^(aspect_ratio - aspect_dist) and i.image_aspect_ratio <= ^(aspect_ratio + aspect_dist),
       limit: 20
   end
 
diff --git a/lib/philomena/processors.ex b/lib/philomena/processors.ex
index c9f0d576..3f745795 100644
--- a/lib/philomena/processors.ex
+++ b/lib/philomena/processors.ex
@@ -6,31 +6,40 @@ defmodule Philomena.Processors do
   alias Philomena.Mime
   alias Philomena.Sha512
 
-  @mimes %{
-    "image/gif" => "image/gif",
-    "image/jpeg" => "image/jpeg",
-    "image/png" => "image/png",
-    "image/svg+xml" => "image/svg+xml",
-    "video/webm" => "video/webm",
-    "image/svg" => "image/svg+xml",
-    "audio/webm" => "video/webm"
-  }
+  def mimes(type) do
+    %{
+      "image/gif" => "image/gif",
+      "image/jpeg" => "image/jpeg",
+      "image/png" => "image/png",
+      "image/svg+xml" => "image/svg+xml",
+      "video/webm" => "video/webm",
+      "image/svg" => "image/svg+xml",
+      "audio/webm" => "video/webm"
+    }
+    |> Map.get(type)
+  end
 
-  @analyzers %{
-    "image/gif" => Philomena.Analyzers.Gif,
-    "image/jpeg" => Philomena.Analyzers.Jpeg,
-    "image/png" => Philomena.Analyzers.Png,
-    "image/svg+xml" => Philomena.Analyzers.Svg,
-    "video/webm" => Philomena.Analyzers.Webm
-  }
+  def analyzers(type) do
+    %{
+      "image/gif" => Philomena.Analyzers.Gif,
+      "image/jpeg" => Philomena.Analyzers.Jpeg,
+      "image/png" => Philomena.Analyzers.Png,
+      "image/svg+xml" => Philomena.Analyzers.Svg,
+      "video/webm" => Philomena.Analyzers.Webm
+    }
+    |> Map.get(type)
+  end
 
-  @processors %{
-    "image/gif" => Philomena.Processors.Gif,
-    "image/jpeg" => Philomena.Processors.Jpeg,
-    "image/png" => Philomena.Processors.Png,
-    "image/svg+xml" => Philomena.Processors.Svg,
-    "video/webm" => Philomena.Processors.Webm
-  }
+  def processors(type) do
+    %{
+      "image/gif" => Philomena.Processors.Gif,
+      "image/jpeg" => Philomena.Processors.Jpeg,
+      "image/png" => Philomena.Processors.Png,
+      "image/svg+xml" => Philomena.Processors.Svg,
+      "video/webm" => Philomena.Processors.Webm
+    }
+    |> Map.get(type)
+  end
 
   @versions [
     thumb_tiny: {50, 50},
@@ -47,8 +56,8 @@ defmodule Philomena.Processors do
     with upload when not is_nil(upload) <- params["image"],
          file <- upload.path,
          {:ok, mime} <- Mime.file(file),
-         mime <- @mimes[mime],
-         analyzer when not is_nil(analyzer) <- @analyzers[mime],
+         mime <- mimes(mime),
+         analyzer when not is_nil(analyzer) <- analyzers(mime),
          analysis <- analyzer.analyze(file),
          changes <- analysis_to_changes(analysis, file, upload.filename)
     do
@@ -73,9 +82,9 @@ defmodule Philomena.Processors do
 
     mime = image.image_mime_type
     file = image_file(image)
-    analyzer = @analyzers[mime]
+    analyzer = analyzers(mime)
     analysis = analyzer.analyze(file)
-    processor = @processors[mime]
+    processor = processors(mime)
     process = processor.process(analysis, file, @versions)
 
     apply_edit_script(image, process)
diff --git a/lib/philomena/processors/gif.ex b/lib/philomena/processors/gif.ex
index 1135c749..4ddb6bef 100644
--- a/lib/philomena/processors/gif.ex
+++ b/lib/philomena/processors/gif.ex
@@ -21,6 +21,12 @@ defmodule Philomena.Processors.Gif do
     %{replace_original: optimize(file)}
   end
 
+  def intensities(analysis, file) do
+    {:ok, intensities} = Intensities.file(preview(analysis.duration, file))
+    intensities
+  end
+
+  
   defp optimize(file) do
     optimized = Briefly.create!(extname: ".gif")
 
diff --git a/lib/philomena/processors/jpeg.ex b/lib/philomena/processors/jpeg.ex
index 2ccd25b8..eae7ab08 100644
--- a/lib/philomena/processors/jpeg.ex
+++ b/lib/philomena/processors/jpeg.ex
@@ -18,6 +18,12 @@ defmodule Philomena.Processors.Jpeg do
 
   def post_process(_analysis, _file), do: %{}
 
+  def intensities(_analysis, file) do
+    {:ok, intensities} = Intensities.file(file)
+    intensities
+  end
+
+  
   defp strip(file) do
     stripped = Briefly.create!(extname: ".jpg")
 
diff --git a/lib/philomena/processors/png.ex b/lib/philomena/processors/png.ex
index 9e56d9e7..83ca0d59 100644
--- a/lib/philomena/processors/png.ex
+++ b/lib/philomena/processors/png.ex
@@ -18,6 +18,12 @@ defmodule Philomena.Processors.Png do
     %{replace_original: optimize(file)}
   end
 
+  def intensities(_analysis, file) do
+    {:ok, intensities} = Intensities.file(file)
+    intensities
+  end
+
+
   defp optimize(file) do
     optimized = Briefly.create!(extname: ".png")
 
diff --git a/lib/philomena/processors/svg.ex b/lib/philomena/processors/svg.ex
index cdae03db..8a1d72b4 100644
--- a/lib/philomena/processors/svg.ex
+++ b/lib/philomena/processors/svg.ex
@@ -16,6 +16,12 @@ defmodule Philomena.Processors.Svg do
 
   def post_process(_analysis, _file), do: %{}
 
+  def intensities(_analysis, file) do
+    {:ok, intensities} = Intensities.file(preview(file))
+    intensities
+  end
+
+
   defp preview(file) do
     preview = Briefly.create!(extname: ".png")
 
diff --git a/lib/philomena/processors/webm.ex b/lib/philomena/processors/webm.ex
index aad0923d..96d3b412 100644
--- a/lib/philomena/processors/webm.ex
+++ b/lib/philomena/processors/webm.ex
@@ -20,6 +20,12 @@ defmodule Philomena.Processors.Webm do
 
   def post_process(_analysis, _file), do: %{}
 
+  def intensities(analysis, file) do
+    {:ok, intensities} = Intensities.file(preview(analysis.duration, file))
+    intensities
+  end
+
+  
   defp preview(duration, file) do
     preview = Briefly.create!(extname: ".png")
 
diff --git a/lib/philomena_web/controllers/search/reverse_controller.ex b/lib/philomena_web/controllers/search/reverse_controller.ex
new file mode 100644
index 00000000..56c56344
--- /dev/null
+++ b/lib/philomena_web/controllers/search/reverse_controller.ex
@@ -0,0 +1,65 @@
+defmodule PhilomenaWeb.Search.ReverseController do
+  use PhilomenaWeb, :controller
+
+  alias Philomena.Processors
+  alias Philomena.DuplicateReports
+  alias Philomena.Repo
+  import Ecto.Query
+
+  plug PhilomenaWeb.ScraperPlug, [params_key: "image", params_name: "image"] when action in [:create]
+
+  def index(conn, _params) do
+    render(conn, "index.html", images: nil)
+  end
+
+  def create(conn, %{"image" => image_params}) do
+    images =
+      image_params["image"].path
+      |> mime()
+      |> analyze()
+      |> intensities()
+      |> case do
+        :error ->
+          []
+
+        {analysis, intensities} ->
+          {width, height} = analysis.dimensions
+          aspect = width / height
+          dist = normalize_dist(image_params)
+
+          DuplicateReports.duplicates_of(intensities, aspect, dist, dist)
+          |> preload(:tags)
+          |> Repo.all()
+      end
+
+    conn
+    |> render("index.html", images: images)
+  end
+
+  defp mime(file) do
+    {:ok, mime} = Philomena.Mime.file(file)
+
+    {mime, file}
+  end
+
+  defp analyze({mime, file}) do
+    case Processors.analyzers(mime) do
+      nil -> :error
+      a   -> {a.analyze(file), mime, file}
+    end
+  end
+
+  defp intensities(:error), do: :error
+  defp intensities({analysis, mime, file}) do
+    {analysis, Processors.processors(mime).intensities(analysis, file)}
+  end
+
+  # The distance metric is taxicab distance, not Euclidean,
+  # because this is more efficient to index.
+  defp normalize_dist(%{"distance" => distance}) do
+    distance
+    |> String.to_float()
+    |> max(0.01)
+    |> min(1.0)
+  end
+end
\ No newline at end of file
diff --git a/lib/philomena_web/router.ex b/lib/philomena_web/router.ex
index 4f99d933..a75ed0de 100644
--- a/lib/philomena_web/router.ex
+++ b/lib/philomena_web/router.ex
@@ -98,6 +98,9 @@ defmodule PhilomenaWeb.Router do
       resources "/autocomplete", AutocompleteController, only: [:show], singleton: true
     end
     resources "/tags", TagController, only: [:index, :show]
+    scope "/search", Search, as: :search do
+      resources "/reverse", ReverseController, only: [:index, :create]
+    end
     resources "/search", SearchController, only: [:index]
     resources "/forums", ForumController, only: [:index, :show] do
       resources "/topics", TopicController, only: [:show] do
diff --git a/lib/philomena_web/templates/search/reverse/index.html.slime b/lib/philomena_web/templates/search/reverse/index.html.slime
new file mode 100644
index 00000000..0d485b84
--- /dev/null
+++ b/lib/philomena_web/templates/search/reverse/index.html.slime
@@ -0,0 +1,74 @@
+h1 Reverse Search
+
+= form_for :image, Routes.search_reverse_path(@conn, :create), [multipart: true], fn f ->
+  p
+    ' Basic image similarity search. Finds uploaded images similar to the one
+    ' provided based on simple intensities and uses the median frame of GIFs;
+    ' very low contrast images (such as sketches) will produce poor results
+    ' and, regardless of contrast, results may include seemingly random images
+    ' that look very different.
+
+  .image-other
+    #js-image-upload-previews
+    p Upload a file from your computer, or provide a link to the page containing the image and click Fetch.
+    .field
+      = file_input f, :image, class: "input js-scraper"
+
+    .field.field--inline
+      = url_input f, :scraper_url, class: "input input--wide js-scraper", placeholder: "Link a deviantART page, a Tumblr post, or the image directly"
+      button.button.button--separate-left#js-scraper-preview type="button" title="Fetch the image at the specified URL" data-disable-with="Fetch"
+        ' Fetch
+
+    .field-error-js.hidden.js-scraper
+
+  h4 Optional settings
+
+  .field
+    = label f, :distance, "Match distance (suggested values: between 0.2 and 0.5)"
+    br
+    = number_input f, :distance, value: 0.25, min: 0, max: 1, step: 0.01, class: "input"
+
+  .field
+    = submit "Reverse Search", class: "button"
+
+= cond do
+  - is_nil(@images) ->
+  
+  - Enum.any?(@images) ->
+    h2 Results
+
+    table
+      tr
+        th &nbsp;
+        th Image
+        th &nbsp;
+      
+      = for match <- @images do
+        tr
+          td
+            h3 = link "##{match.id}", to: Routes.image_path(@conn, :show, match)
+            p
+              = if match.source_url not in [nil, ""] do
+                span.source_url
+                  = link "Source", to: match.source_url
+              - else
+                ' Unknown source
+
+          td
+            = render PhilomenaWeb.ImageView, "_image_container.html", image: match, size: :thumb, conn: @conn
+
+          td
+            h3
+              = match.image_width
+              | x
+              => match.image_height
+              ' -
+              => round(match.image_size / 1024)
+              ' KiB
+
+            = render PhilomenaWeb.TagView, "_tag_list.html", tags: Tag.display_order(match.tags)
+
+  - true ->
+    h2 Results
+    p
+      ' We couldn't find any images matching this in our image database.
\ No newline at end of file
diff --git a/lib/philomena_web/views/search/reverse_view.ex b/lib/philomena_web/views/search/reverse_view.ex
new file mode 100644
index 00000000..498deefa
--- /dev/null
+++ b/lib/philomena_web/views/search/reverse_view.ex
@@ -0,0 +1,5 @@
+defmodule PhilomenaWeb.Search.ReverseView do
+  use PhilomenaWeb, :view
+
+  alias Philomena.Tags.Tag
+end