Add image decoding support with image crate

src/apis/assets.rs

@@ -1,5 +1,6 @@
 //! Assets API - Manage photos and videos
 
+use std::io::Cursor;
 use std::path::Path;
 
 use crate::{
@@ -44,6 +45,37 @@ impl ThumbnailResponse {
     pub fn into_data(self) -> bytes::Bytes {
         self.data
     }
+
+    /// Decode the image data into a DynamicImage
+    ///
+    /// # Errors
+    /// Returns an error if the content type is not supported or if decoding fails
+    ///
+    /// # Example
+    /// ```rust,ignore
+    /// use immich_sdk::Client;
+    ///
+    /// # async fn example() -> Result<(), Box<dyn std::error::Error>> {
+    /// let client = Client::from_url("https://immich.example.com")?;
+    /// let asset_id = "your-asset-id".parse()?;
+    /// let response = client.assets().thumbnail(asset_id).execute().await?;
+    /// let image = response.decode()?;
+    /// println!("Image size: {}x{}", image.width(), image.height());
+    /// # Ok(())
+    /// # }
+    /// ```
+    pub fn decode(&self) -> Result<image::DynamicImage> {
+        // Get image format from content type
+        let format = image::ImageFormat::from_mime_type(&self.content_type)
+            .ok_or_else(|| ImmichError::Image(
+                format!("Unsupported content type: {}", self.content_type)
+            ))?;
+
+        // Create reader with the format and decode
+        image::ImageReader::with_format(Cursor::new(&self.data), format)
+            .decode()
+            .map_err(|e| ImmichError::Image(e.to_string()))
+    }
 }
 
 /// API for managing assets (photos and videos)