I agree with levlaz regarding the photo being in harmony with the body background and regarding reponsiveness. I’m really not a web design expert, but overall the page looks good. Couple of questions/remarks.
What’s the use of the border-radius in #img-div? It doesn’t seem to make any difference when it’s commented or put to e.g. 50%
Same question regarding ‘display: block;’ in the div for the text columns. Div is already block level, so I think it has no added value.
Why are you using different widths for your four text columns? Isn’t it better practice to make them all the same width for such kind of page? You also can have less coding by grouping the properties with the same values for the four id’s into a fifth one. That way you don’t have to repeat them.