I seem to have a similar problem, with my digital camera sometimes. A big pixel CCD tends to make a HUGE file (to increase resolution, digitally).(I'm confused...usually there is an option to upload and post a photo "from a file", or "from a link".)
Going directly from camera seems to involve a problem with file sizes (I was doing this in some Google e-mails recently). Seems the best way is to run the image through another processing program, to "compress" it. (??) I'm still figuring a lot of this technical stuff out).
I always thought that "JPG" was already a compression method....but, your pics are IN "JPG" (?)