I think it is time for one of my periodic reminders to keep the file
size of your pictures down to about 40-50Kb.
My process is to use a program like Photoshop or Picture It to first
set the picture to 72 dpi, then I resample the image to approximately
4 X 5 inches and when I save it, set the jpg compression to get down
to the file size I want. Setting the dpi and the picture size lets me
control the display size.
50KB or smaller is the recommended size and lots of folks easily get
them under 40KB. If you want to send multiple pictures in the same
message, please limit your total message size to 200KB but individual
picture sizes should still be in the 40 -50 KB range (or less).