E mail Mystery,,,,,Help

I converted my e mail account as directed by an e mail from Comcast when they were ttransitiong all of the Time Warner users over to Comcast.

My new e mail adress works fine on both incoming and outgoing mail. The problem is with imbedded phots and or attachments...........I can receive any and everything sent to me ,can open and read it all but cannot forward any of it on to others. The text will go intact but thats it all other info shows up as an outline square with a small square inside and a red "X" with in that small square.

Whats the problemmmmmmmmmmm???????? Comcast Tech Support is stumped.

dick