When looking in Firefox's awesome tool, Firebug, I see html code that I want to change.

Firebug will give me the CSS code that's related and even tell me what line to find it on, but it doesn't point me to the correct PHP file.

How can I use the code I find in Firebug in conjunction with the Developer's Toolkit, to locate the appropriate file?

Example:

On my Step 2 of 3 - Payment Information Page in Zen Cart, I find this code using Firebug:

<fieldset><legend>Payment Method</legend>

<strong>We accept:</strong>

<img width="37" height="23" alt="" src="includes/templates/barebones/images/icons/cc1.gif"/>

<img width="37" height="23" alt="" src="includes/templates/barebones/images/icons/cc2.gif"/>

<img width="37" height="21" alt="" src="includes/templates/barebones/images/icons/cc3.gif"/>

<img width="37" height="21" alt="" src="includes/templates/barebones/images/icons/cc5.gif"/>

<br class="clearBoth"/>
In this example, I want to add Alt Text to this code so that the images will be accessible by screen readers for the visually impaired.

What part of the above code would I paste into the Developer's Tool Kit in order to locate the appropriate PHP file?

Or, is there another method I should be using to figure out how to locate the PHP file that contains the code I'm able to see using Firebug?

I've tried pasting this single line of code, for example, in to the bottom most box of the Developer's Tool Kit, but got no results.

<img width="37" height="21" alt="" src="includes/templates/barebones/images/icons/cc5.gif"/>

I think the Developer's Tool Kit is awesome, and I've read the tutorials about how to use it, but I think having some info about how to use it in conjunction with Firebug would come in handy for a lot of folks.

Suggestions?