My switch stack consists of 3750G-48TS (as master) and 3750-24TS & PS as slave. May I know whether I should choose the IOS compatible with 3750G-48TS or 3750-24TS/PS?
It's the same image for all those types you mention.
If you had 3750E switches, they are running the -universal- image, where you have to purchase license for the feature you will use, but the original 3750 series switches all use the same images. Cisco just makes it look somewhat confusing by showing all switch models in the software download area.