diff --git a/app/controllers/templates_detect_fields_controller.rb b/app/controllers/templates_detect_fields_controller.rb
index 56b06cd5..a0cd54ff 100644
--- a/app/controllers/templates_detect_fields_controller.rb
+++ b/app/controllers/templates_detect_fields_controller.rb
@@ -16,7 +16,12 @@ class TemplatesDetectFieldsController < ApplicationController
     page_number = params[:page].presence&.to_i
 
     documents.each do |document|
-      io = StringIO.new(document.download)
+      io =
+        if document.image?
+          StringIO.new(document.preview_images.joins(:blob).find_by(blob: { filename: ['0.png', '0.jpg'] }).download)
+        else
+          StringIO.new(document.download)
+        end
 
       Templates::DetectFields.call(io, attachment: document, page_number:) do |(attachment_uuid, page, fields)|
         sse.write({ attachment_uuid:, page:, fields: })
diff --git a/lib/templates/detect_fields.rb b/lib/templates/detect_fields.rb
index 4a620d1b..dae0ce1e 100755
--- a/lib/templates/detect_fields.rb
+++ b/lib/templates/detect_fields.rb
@@ -77,7 +77,7 @@ module Templates
                                  split_page: false, aspect_ratio: false, padding: nil, page_number: nil)
       return [[], nil] if page_number && page_number != 0
 
-      image = ImageUtils.load_vips(io.read, content_type: attachment.content_type)
+      image = ImageUtils.load_vips(io.read)
 
       fields = inference.call(image, confidence:, nms:, nmm:, split_page:,
                                      temperature:, aspect_ratio:, padding:)