Cache image that it's path is fetched through DB

My question is how should I cache images that are loaded by an path on the DB.

I simply get and return the image like:

/**
 * Render an image
 *
 * @param string $slug
 * @return Response
 */
public function renderSlug($slug)
{
    try {
        $image = Image::where('slug', '=', $slug)->firstOrFail();
        $file = File::get($image->getFullPath());
    }
    catch ( \Exception $e ) {
        return Response::json('{}', 404);
    }
    return Response::make($file, 200,  ['content-type' => 'image/jpg']);
}

So I'm fetching the path from DB, and I'm wondering if I should cache path, image or cache nothing at all.

I've looked into the docs about caching, I though doing it like this:

/**
 * Render an image
 *
 * @param string $slug
 * @return Response
 */
public function renderSlug($slug)
{
    try {
        $cacheKey = 'image.' . $slug;
        if(! Cache::has($cacheKey)) {
            $image = Image::where('slug', '=', $slug)->firstOrFail();
            Cache::put($cacheKey, 'value', 10);
        }

        $file = File::get(Cache::get($cacheKey));
    }
    catch ( \Exception $e ) {
        return Response::json('{}', 404);
    }
    return Response::make($file, 200, ['content-type' => 'image/jpg']);
}

Questions:

1. Should I cache anything? (image, path, or nothing)


2. How should I cache it?