Ravi,
Answering in reverse order:
#3. There is no problem or inability to transfer images in Win8.1. Not clear what is meant, in this case, by "partial image"; certainly an image can be saved & then cropped in Paint.
#2. This has been adequately answered, already. The OS has no issue, or bug to make it culpable.
#1. False.
Anything in Win8.1 can be Pinned to Start and or Taskbar. There are 2 methods to achieve this.
A. As shown in the screenshot via Search
B. Using ALL Applications, Rt Clk desired item > Open File Location. Once there, Rt Clk & again, choose Pin to Start & or Pin to Taskbar.
Personally, have not found any lack of functionality, inability to do things or features missing in Win8.1. Does everything as well or better than prior Windows. I am totally happy about Windows 8.1 (or 8.0, for that matter).
Cheers,
Drew