If you have a drawing programme and you resize to <92kb on disk they'll definitely attach (the actual limit is 99kb but I've had trouble attaching 98, 97, etc..)
I have a macbook. What I do: when I''m in iPhoto, I select the picture I want, export it, (I use high quality and medium size and that usually keeps me under the 100KB file size limit) and give it a file name of something long and not common.