Unable to open copied files from computer to device (mount  as disk drive) - HTC Desire S I connected my phone as a disk drive and put some files ( .png ,.jpg ,.swf ) in the sdcard.
I am unable to open those files on the phone.  I am unable to find those files in the gallery of the device, either.

When I checked details from Astro file manager it is showing the extension .cp$ on all the file, as in filename.png.cp$

I am not getting what is the problem??
The transfer was probably corrupted.  The problem is probably with the host OS, and not with your phone.

What OS and what program were you using to copy the files?  Did you remember to "eject" the phone from the computer to make sure everything was synchronized?

Are the files on the phone the right size?  If you plug the phone back into the computer can you look at them successfully there?  (Or try copying them off and looking at the copies.)