posting from a second computer, experiments

Well, I have no idea how to post from this mac computer.  Today I uploaded a picture from my camera that went directly to iphoto and I have no idea how to get it from there onto my blog.  This one was saved into a picassa web album :  how, I don't know!  I uploaded it a couple of weeks ago.  I didn't get a choice as to where to upload today's picture, it went directly to iphoto, which seems to be now lost in the ether!!! Well, more experimentation needed, clearly.
This is a sampling of some collage and stamping from the Jane Davies Composition course.
OK, more picture tracking!! There must be a way!