diff --git a/src/lib.rs b/src/lib.rs
index cbf98e5..e42b011 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -74,5 +74,5 @@ pub use wrapper::hydrus::Hydrus;
 
 pub mod api_core;
 pub mod error;
-pub(crate) mod utils;
+pub mod utils;
 pub mod wrapper;
diff --git a/src/utils.rs b/src/utils.rs
index e615d37..2fa9107 100644
--- a/src/utils.rs
+++ b/src/utils.rs
@@ -1,11 +1,12 @@
+use crate::api_core::common::FileIdentifier;
 use crate::wrapper::tag::Tag;
 use chrono::{Datelike, Duration};
 
-pub fn string_list_to_json_array(l: Vec<String>) -> String {
+pub(crate) fn string_list_to_json_array(l: Vec<String>) -> String {
     format!("[\"{}\"]", l.join("\",\""))
 }
 
-pub fn number_list_to_json_array<T: ToString>(l: Vec<T>) -> String {
+pub(crate) fn number_list_to_json_array<T: ToString>(l: Vec<T>) -> String {
     format!(
         "[{}]",
         l.into_iter()
@@ -23,7 +24,7 @@ pub fn tag_list_to_string_list(tags: Vec<Tag>) -> Vec<String> {
     tags.into_iter().map(|t| t.to_string()).collect()
 }
 
-pub fn format_datetime<D: Datelike>(datetime: D) -> String {
+pub(crate) fn format_datetime<D: Datelike>(datetime: D) -> String {
     format!(
         "{:04}-{:02}-{:02}",
         datetime.year(),
@@ -32,7 +33,7 @@ pub fn format_datetime<D: Datelike>(datetime: D) -> String {
     )
 }
 
-pub fn format_duration(duration: Duration) -> String {
+pub(crate) fn format_duration(duration: Duration) -> String {
     let mut expression = String::new();
     let days = duration.num_days();
     let hours = duration.num_hours() % 24;
@@ -56,3 +57,18 @@ pub fn format_duration(duration: Duration) -> String {
 
     expression
 }
+
+pub(crate) fn split_file_identifiers_into_hashes_and_ids(
+    files: Vec<FileIdentifier>,
+) -> (Vec<u64>, Vec<String>) {
+    let mut ids = Vec::new();
+    let mut hashes = Vec::new();
+
+    for file in files {
+        match file {
+            FileIdentifier::ID(id) => ids.push(id),
+            FileIdentifier::Hash(hash) => hashes.push(hash),
+        }
+    }
+    (ids, hashes)
+}
diff --git a/src/wrapper/page.rs b/src/wrapper/page.rs
index 93669a2..48f37ea 100644
--- a/src/wrapper/page.rs
+++ b/src/wrapper/page.rs
@@ -1,5 +1,6 @@
 use crate::api_core::common::{FileIdentifier, PageInformation};
 use crate::error::Result;
+use crate::utils::split_file_identifiers_into_hashes_and_ids;
 use crate::Client;
 
 #[derive(Clone)]
@@ -40,27 +41,26 @@ impl HydrusPage {
 
     /// Adds files to a page
     pub async fn add_files(&self, files: Vec<FileIdentifier>) -> Result<()> {
-        let mut hashes = Vec::new();
-        let mut ids = Vec::new();
+        let (ids, mut hashes) = split_file_identifiers_into_hashes_and_ids(files);
 
-        for file in files {
-            match file {
-                FileIdentifier::ID(id) => ids.push(id),
-                FileIdentifier::Hash(hash) => hashes.push(hash),
-            }
-        }
         // resolve file ids to hashes
-        if ids.len() > 0 && hashes.len() > 0 {
-            while let Some(id) = ids.pop() {
-                let metadata = self
-                    .client
-                    .get_file_metadata_by_identifier(FileIdentifier::ID(id))
-                    .await?;
-                hashes.push(metadata.hash);
-            }
-        }
+        hashes.append(&mut self.resolve_file_ids_to_hashes(ids).await?);
 
-        self.client.add_files_to_page(&self.key, ids, hashes).await
+        self.client
+            .add_files_to_page(&self.key, [].to_vec(), hashes)
+            .await
+    }
+
+    async fn resolve_file_ids_to_hashes(&self, ids: Vec<u64>) -> Result<Vec<String>> {
+        let mut hashes = Vec::new();
+        for id in ids {
+            let metadata = self
+                .client
+                .get_file_metadata_by_identifier(FileIdentifier::ID(id))
+                .await?;
+            hashes.push(metadata.hash);
+        }
+        Ok(hashes)
     }
 }