Add initial image CLI runtime

src/image.ts

@@ -0,0 +1,37 @@
+import { mkdir, writeFile } from "node:fs/promises";
+import { join } from "node:path";
+
+const IMAGES_DIR = "images";
+
+function mediaTypeToExtension(mediaType: string): string {
+	switch (mediaType) {
+		case "image/png":
+			return "png";
+		case "image/jpeg":
+			return "jpg";
+		case "image/webp":
+			return "webp";
+		case "image/gif":
+			return "gif";
+		default:
+			return "bin";
+	}
+}
+
+function createTimestampFileName(mediaType: string): string {
+	const extension = mediaTypeToExtension(mediaType);
+	const timestamp = new Date().toISOString().replace(/[.:]/g, "-");
+	return `${timestamp}.${extension}`;
+}
+
+export async function saveImage(
+	bytes: Uint8Array,
+	mediaType: string,
+): Promise<string> {
+	await mkdir(IMAGES_DIR, { recursive: true });
+
+	const filePath = join(IMAGES_DIR, createTimestampFileName(mediaType));
+	await writeFile(filePath, bytes);
+
+	return filePath;
+}