(1) How to know the uploader of any image downloaded from facebook ?

Photos downloaded from facebook has naming convention like 

10553866_683772571716631_1387821185946217935_o.jpg

Now if you want to go to the profile of the owner of the downloaded photo, just copy the number between first underscore and second underscore , so the number is

683772571716631

Now goto  http://www.facebook.com/68377257...
and you landed at the page of the picture on facebook.
Give it a Try.

(2) How to be greeted by your computer every time you start your computer?

Do you want to be greeted like Iron Man? I know , You don't have smart Operating System Like JARVIS but your windows also can do this for you.
To do this , first make a file Welcome.vbs     .
Open notepad and simply write

    speaks="Welcome back Sir or anything you want."
    Set speech=CreateObject("sapi.spvoice")
    speech.Rate = -3
    speech.Speak speaks

NOTE:-    -3 Denotes the rate of speech , you can change according to your choice .

and save it as Welcome.vbs   .
It will look like this  



Now check if it is working or not so just double click it, it will read the texts .

Next to make it work at windows startup every time for Windows 7/8/8.1 , just put this file to

    C:\Users\<<Username>>\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup\

Note :- You need to unhide the hidden files and folders because the  AppData  folder comes hidden by default in windows.

In Windows vista put this file at

C:\Documents and Settings\All Users\Start Menu\Programs\Startup\

Now on every windows startup it will greet you.

Edit:-The default voice for the speech in Windows 8 is a male voice of Microsoft David. I you want to change it to Microsoft  Hazel's or Microsoft Zira's voice then  To hear these voices and configure them, open Control Panel > All Control Panel Items > Speech Recognition. In the LHS pane click Text to Speech. Here, you can control text to speech properties and hear each of the voices by selecting the voice from the drop-down menu and clicking on the Preview  Voice button.

You can also select the voice speed by moving the slider, the audio output and the preferred audio device by clicking on the Advanced button. 
Thank you  Nakul Bansal  for your suggestion.

(3) Some trick for Gmail users 

To open only unread emails , just type is:unread in search box .
You can also open is:starred , is:read , is:muted , is:chat .



if you want to open unread emails from inbox only then type
is:unread label:inbox  in search box.



For other lables just use label:spam , label:chats e.t.c  and You can combine the keywords according to use.
Source: Quora(Rahul Jha).