JPG files size?

I got a coder to code a PSD to XHTML and he did a very nice job. Now I am trying to add more things. He made various icons out of the design, now I am trying to do the same, but when I save them, the file size is much bigger than the icons he made. I have tried Photoshop and Fireworks I can't get anywhere near to the size of his icons with any of those two keeping the good quality.

How exactly are you saving the files?

Are you using Photoshop's save for web compression?

Yeah. I talk with Michael and he told me I had to save them for web usage.

Thanks!