diff --git a/app/models/resource.rb b/app/models/resource.rb
index ab85889..3cad29e 100644
--- a/app/models/resource.rb
+++ b/app/models/resource.rb
@@ -32,6 +32,20 @@ class Resource < ApplicationRecord
   alias_method :attachable_content_iiif_url, :content_iiif_url
   alias_method :attachable_content_thumbnail_url, :content_thumbnail_url
 
+  def self.with_attachment(name)
+    subquery = attachment_subquery(name)
+    subquery = yield subquery if block_given?
+
+    where(subquery.arel.exists)
+  end
+
+  def self.without_attachment(name)
+    subquery = attachment_subquery(name)
+    subquery = yield subquery if block_given?
+
+    where.not(subquery.arel.exists)
+  end
+
   def content_base_url
     return attachable_content_base_url unless content_converted.attached?
 
@@ -72,6 +86,13 @@ def pdf?
 
   private
 
+  def self.attachment_subquery(name)
+    ActiveStorage::Attachment
+      .where(ActiveStorage::Attachment.arel_table[:record_id].eq(Resource.arel_table[:id]))
+      .where(record_type: Resource.to_s)
+      .where(name: name)
+  end
+
   def after_create
     # Convert the image to a TIFF
     ConvertImageJob.perform_later(self.id)
diff --git a/app/services/images/convert.rb b/app/services/images/convert.rb
index 6f272fd..89326a2 100644
--- a/app/services/images/convert.rb
+++ b/app/services/images/convert.rb
@@ -16,6 +16,8 @@ def self.to_tiff(file)
       convert << '8'
       convert << '-compress'
       convert << 'jpeg'
+      convert << '-alpha'
+      convert << 'remove'
       convert << "ptif:#{output_path}"
       convert.call
 
diff --git a/lib/tasks/iiif.rake b/lib/tasks/iiif.rake
index 7c4cf94..a08e0e2 100644
--- a/lib/tasks/iiif.rake
+++ b/lib/tasks/iiif.rake
@@ -2,7 +2,14 @@ namespace :iiif do
 
   desc 'Converts the source images to pyramidal TIFFs for all resources'
   task convert_images: :environment do
-    Resource.all.in_batches do |resources|
+    query = Resource.with_attachment('content') do |subquery|
+      subquery
+        .joins(:blob)
+        .where('active_storage_blobs.byte_size > ?', 0)
+        .where('active_storage_blobs.content_type ILIKE \'%image%\'')
+    end
+
+    query.in_batches do |resources|
       resources.pluck(:id).each do |resource_id|
         ConvertImageJob.perform_later(resource_id)
       end
@@ -12,13 +19,45 @@ namespace :iiif do
   desc 'Converts the source images to pyramidal TIFFs for resources with no converted content'
   task convert_images_empty: :environment do
     query = Resource
-              .where.not(
-                ActiveStorage::Attachment
-                  .where(ActiveStorage::Attachment.arel_table[:record_id].eq(Resource.arel_table[:id]))
-                  .where(record_type: Resource.to_s, name: 'content_converted')
-                  .arel
-                  .exists
-              )
+              .without_attachment('content_converted')
+              .with_attachment('content') do |subquery|
+                subquery
+                  .joins(:blob)
+                  .where('active_storage_blobs.byte_size > ?', 0)
+                  .where('active_storage_blobs.content_type ILIKE \'%image%\'')
+              end
+
+    query.in_batches do |resources|
+      resources.pluck(:id).each do |resource_id|
+        ConvertImageJob.perform_later(resource_id)
+      end
+    end
+  end
+
+  desc 'Converts the source images to pyramidal TIFFs for resources by the specified MIME type'
+  task convert_images_by_type: :environment do
+    # Parse the arguments
+    options = {}
+
+    opt_parser = OptionParser.new do |opts|
+      opts.banner = 'Usage: rake iiif:convert_images_by_type [options]'
+      opts.on('-t', '--type ARG', 'Image MIME type') { |type| options[:type] = type }
+    end
+
+    args = opt_parser.order!(ARGV) {}
+    opt_parser.parse!(args)
+
+    if options[:type].blank?
+      puts 'Please specify a MIME type...'
+      exit 0
+    end
+
+    query = Resource.with_attachment('content') do |subquery|
+      subquery
+        .joins(:blob)
+        .where('active_storage_blobs.byte_size > ?', 0)
+        .where('active_storage_blobs.content_type = ?', options[:type])
+    end
 
     query.in_batches do |resources|
       resources.pluck(:id).each do |resource_id|