Caching Files in the Browser - asp.net

Question

By using the below function I am caching js, css file in the browser.
Like wise I want to cahe the Image in the browser.
private static void CacheOrFetchFromServer(string relativePath, string absolutePath, HttpContext context)
{
Cache cache = HttpRuntime.Cache;
string content;
if (cache[relativePath] == null)
{
Encoding encoding = Encoding.GetEncoding(DefaultEncodingCodePage);
CacheDependency dependency = new CacheDependency(absolutePath);
content = File.ReadAllText(absolutePath, encoding);
cache.Insert(relativePath, content, dependency);
}
else
{
content = cache[relativePath].ToString();
}
using (StreamWriter sw = new StreamWriter(context.Response.OutputStream))
{
sw.Write(content);
}
}
I had tried the below one to cache the image. But it didn't show the image.
private static void CacheOrFetchImageFileFromServer(string relativePath, string absolutePath, HttpContext context)
{
string extension = System.IO.Path.GetExtension(relativePath);
if (extension.ToUpper() == ".JPG" || extension.ToUpper() == ".PNG" || extension.ToUpper() == ".GIF" || extension.ToUpper() == ".TIFF")
{
Cache cache = HttpRuntime.Cache;
System.Drawing.Image imgPhoto = null;
if (cache[relativePath] == null)
{
Encoding encoding = Encoding.GetEncoding(DefaultEncodingCodePage);
CacheDependency dependency = new CacheDependency(absolutePath);
FileStream fs = File.OpenRead(absolutePath);
byte[] data = new byte[fs.Length];
fs.Read(data, 0, data.Length);
MemoryStream ms = new MemoryStream(data);
Bitmap bmp = new Bitmap(ms);
imgPhoto = System.Drawing.Image.FromFile(absolutePath);
cache.Insert(relativePath, bmp, dependency);
}
else
{
imgPhoto = (Image) cache[relativePath];
}
context.Response.Write(absolutePath);
//using (StreamWriter sw = new StreamWriter(context.Response.OutputStream))
//{
// sw.Write(absolutePath);
//}
}
}

Answer 1

I'm not sure I understand what you're doing here.
First of all, the Cache object in asp.net is used to cache data on the server side, not on the client side (browser).
Caching of files, specially css, JavaScript and images, is done by the browser automatically, you don't have to do this manually for every file. And even if you had to do this manually, this isn't the way - it looks like you're just creating a copy of the file on the server's cache (I havn't done tests, but I trust Microsoft and assume this is already done in some way, and your way is actually slower).
If you want greater control over client side caching, you can enable content expiration on the IIS.