I have integrated sharekit in my iPhone Application.My app used to be around 1.5MB and all of a sudden it became 6.3 MB after integrating sharekit.And I am using only Twitter and Facebook Sharing.Is there a way to Reduce the size of my app?.or is there any other way for sharing? My Deployment Target is 4.3
Also you can use ImageOptim to reduce the file size of your images. Just download, open and drag and drop a folder or all your images onto the interface.
There is even a case study on how well this tool can be used to shrink your iOS-Apps:
http://imageoptim.com/tweetbot.html
Additionally I would delete the ShareKit components you do not need.