Some companies block such images, like Verizon and T-Mobile. Not sure what other are also blocking such.
They want you to pay an extra fee to view these images.
Do you have the picture messaging plan discussed here? Looks like they want you to have a picture messaging plan to be able to receive them. I guess that way there's no guessing if you want to get picture messages or not.
I have a Motarola Razr, and am a subscriber to US Cellular. I have friends sending me picture messages, and as I understand it, you are supposed to be able to receive them for free. But I don't receive them, or a message with a code to retrieve the picture online. Any suggesions?