How to center image in a post

How can I center an image in my post manually? I am using this code. Its not supposed to wrap around the text.

<img src="http://www.thisismyimage.jpg">

 

If you are using the editor correctly, there is a button in the toolbar.

 

<img src="image_url.jpg" aliign="center" alt="image" title="image title">

CMIIW

 

you dont have to need any kind of support you just need help how to use tiny mce editor in wordepress. in tiny mce editor there is an image insert link by using you can insert the image in post data,you can also reduce the dimension of pic by just click over the image. in drag in any direction either you want to reduce or increase the dimension.i hope this will help you? you can also use html source code to add the content to post