uploading photos to facebook takes too much time in firefox 12 .

I am using Mozilla Firefox Browser with windows7 OS. It is working fine and smooth. When I installed new updated in Firefox it started to give me a trouble. my internet is working very slow and When I try to upload photo in Facebook even small file of 300-400 KB takes around 5min. which is uploaded by internet explorer in around 20-30sec and working fine. Firefox is my default browser and i always comfortable with it. I uninstall Firefox browser and after rebooting the machine reinstall the browser but still have a same problem. I search on internet many have same problem in Mozilla Firefox 12 version.

I am also having same problem in my Lenovo laptop. I am suing Mozilla Firefox with Windows Xp OS. When I installed new version Of Firefox I started to getting problem. My internet is working too slow and uploading Photos to Social site is take too much time. I have deleted cache, history and cookies everything from browser but cannot fix the problem. I think it is network problem but when I saw in all the other browser loading of pages working fine so I get it is browser problem. So, I try to get some help from Google and make search about my problem and search on many website but not get any solution. So, finally I uninstall Firefox and Further reinstall Older version. Now I got my speed of internet in Firefox.

I understand your problem because once time I got same problem in my laptop. I try one trick with my browser which make your browser more faster. this trick is known as Pipelining trick. Normally the browser will make one request to a web page at a time. When you enable pipelining it will make several request at once, which can speed up page loading and boosting your internet. I give you step how to use this trick which help you follow it. I think this trick will help you.
Step :

1. Type "about:config" into the address bar and hit Enter.
2. Look for “network.http.keep-alive”. If it’s false, double-click that line and to change it to true.
3. Make sure “network.http.version” is set to “1.1″.
4. Look for “network.http.pipelining”. If it’s false, double-click that line and change it to true.
5. Set "network.http.proxy.pipelining" to true by double-clicking it.
6. Set "network.http.pipelining.maxrequests" to 8 by double-clicking it. This means it will make 8 requests at once. There is no point setting it higher than 8 as it is capped at 8 max. The default value for this setting is 4.
7. Optional: Right-click anywhere and select New-> Integer. Name it "nglayout.initialpaint.delay" and set its value to "0". This value is the amount of time the browser waits before it shows you the information it receives. This is particularly helpful on pages with search bars.

I am using Firefox from last few years and get great performance and support from Mozilla. I love Mozilla Firefox.I prefer Firefox because have several reason. I am regularly update my Firefox. I will give you some solution try it.
Everyday clear all history, cookies and cache from browser and make it faster.
If you installed any extension and themes then remove it and switch to default theme sometime it gives trouble.
Check for spyware and Malware by your antivirus program.
Go to add on and check for any update.
If you running Web Developer add on, it disabled Firefox from even using a cache. So, It was loading everything from the net. So enable the Firefox to use cache.