feat: image resizing (#5446)

Add image resizing on the client side to reduce load on the API

codex-rs/utils/image/src/error.rs

@@ -0,0 +1,25 @@
+use image::ImageFormat;
+use std::path::PathBuf;
+use thiserror::Error;
+
+#[derive(Debug, Error)]
+pub enum ImageProcessingError {
+    #[error("failed to read image at {path}: {source}")]
+    Read {
+        path: PathBuf,
+        #[source]
+        source: std::io::Error,
+    },
+    #[error("failed to decode image at {path}: {source}")]
+    Decode {
+        path: PathBuf,
+        #[source]
+        source: image::ImageError,
+    },
+    #[error("failed to encode image as {format:?}: {source}")]
+    Encode {
+        format: ImageFormat,
+        #[source]
+        source: image::ImageError,
+    },
+}