Right click on the image bar, with the title, exit button, etc. There will be an option for "image size", so click on that, and from there, that will solve your problem.
i did that with the painter program that comes with windows, i just open the photo , size about 1 mega or so, then i go and save it as; and give a new name with the jpg format, the result is a few 100 kb pic, vioala!!
