Can no longer send pictures in text that I once did. "Unsupported file type"

Arug

The other day my phone began saying I could not longer send pictures in MMS. Pictures I sent the previous week are now an unsupport file type.  They are .jpg and .pngs.  I have to take a screenshot of them all now, crop out the excess stuff, and then send them.

Salisbury

Taking a screenshot or cropping will tell nothing  .mov or .wmv format for example looks the same, one is supported by Apple QuickTime the other with Microsoft Windows Media Player, it's all in the codec. What is the exact file type? Or in what format were they saved and with what?