Hi, I am displaying one image using Texture Mapping. After that I have applied some filters on the image data. But it is not affecting on the Texture. Is it possible to set the texture image data without glTexImage2d?

Man, be a little more specific.
1.) If the filter has been applied in SW to the image you downloaded to the texture earlier, you have to redownload the image and draw the picture again.
Downloading a teximage again is fastest with glTexSubImage2D if the size hasn’t changed.
2.) If the filter has been applied to the screen image and you want to get that back into the texture the fastest way is to call glCopyTexImage (set the correct glReadBuffer!).
Redrawing the picture will show the newly filtered picture now. This is how the spacy blur effects in the MediaPlayer can be done.
3.) A readback from teximage data can be done with glGetTexImage. This is a sort of memcopy.