Does any one knows the iOS for any switch of 48 ports which we can use in GNS3?

There is no simulation software available to simulate actual Cisco Switch IOS like GNS3 for routers.
But you can use router IOS Image in GNS3 to perform some limited number of switching command by adding "NM-16ESW" slot and preferred IOS is from3700 series (c3725-advipservicesk9-mz.124-3, c3745-a3jk9s-mz.123-4.T2).

There are no IOS for switches in GNS but what we do is that we use routers IOS with switching features and increase the number of ports in that to get gone switching feature.
But with limited number of ports

Unfortunately, there is no way we can simulate switch in GNS3. Though; you can configure router to use NM-16ESW and then you can apply some of the switch configurations.

 

Switches work on the ASIC chip which is a hardware control chip, and its impossible to simulate ASIC.

 

Thanks.

below you can find the IOS for the following switches2950 &2960 : http://www.iosdownload.org/cisco--switch-ios-download.html

guys thanks for reply, @ Haris i did the same.
but it will support up to16or24 ports.
and can add multiple slots but he interface will change.
e.g f0/1-f0-24 and f1/0-f1/24.
i want to practice the ccie lab thus looking for some way to add upto48 ports under one like f0/1-f0/48.