Whatever 'photo program' you have to view them on your monitor, will usually have a 'resize' tab. I use MGI PhotoSuite (the Photo Shop Bud sent me, I never could get it installed) ...
Then, what I do, is keep cutting it in size by quarters, and try to send it, until it takes it.
The very large photos you are getting from you camera, are most likely due to the shot being taking at the highest resolution (most megapixels) which make better 8x10 photos.
Try taking pictures at the lowest setting the camera will give you ... and see if that works.