What would I need to change to change the words 'Buy It Now' and 'Bid' to buttons or icons - instead of displaying the words, display a .png or .gif icon?
That would require a couple edits to the template.php You would need to provide the graphics for those buttons
I would also like to change the font size (maybe the color too) of the bid price, shipping price and buy in now price - is this possible?
An easy way to do that would be look for the text in
Then just find the text entry for example
$txt['class_example'] = 'my text here'';
And change it to
$txt['class_example'] = '<font color="#FF0000">my text here</font>'';
That would change it to red in the above example and you can use any html tags in the language strings file.
After you make a change to the language strings in SMF 2.0 you have to go to file maintenance clear cache