Pictures in Mail

[rich northouse]

I am running Mail 1.3.8(V618) on a 733 MhZ Mac under OS 10.3.4.  Many 
times when I send photos and/or graphics to my friends with PCs, they 
don't receive the photos/graphics. What is really odd, is that many of 
these photos/graphics I received from different friends, also with PCs! 
  Many times I can't read some of their stuff -- I get little blue boxes 
instead of photos/graphics.

Do I have something set wrong?  A switch not thrown?

Thanks for your help.


rich