you need to reduce the size of the picture
there are a number of free software packages to do that
you may have been given one with the camera
set the pixel size of the photo to make the longest side about 500 pixels - thats good enough to see on most screens
irfanview
www.irfanview.com
ez thumbs
whats the make/model of camera
canon comes with zoombrowser and has an email size option