New reply/post buttons edit

[Fun-Masti]

Ok, this might really be a very dumb question to ask, but I really need to ask this.
The buttons "+ Post new thread" or "+reply to thread". These are not images but simply text on a colored background, in shape of a button. However, buttons in images folder do have images for the same purpose. I was wondering where is the option to use those images instead of the text buttons for the same? Is there an option for this or an edit is required?

[ikopylov]

Give me a link to your website, I'll help you

[Fun-Masti]

I am working it on localhost, havent uploaded online yet. But I can give example for it.
Here, on vbulletin.org (image1) images are being used.
While in image2 from my website text button is used.

So, what I want to do is use image like used in vbulletin.org, instead of text button in default (image2)