Unknown or invalid JPEG marker

[ianberry]

I'm trying to open some important holiday photos but I have about 100 photos that WILL NOT OPEN!!! All I get is a "Could not open" message ending "because an unknown or invalid JPEG marker type is found".
Whilst away on holiday the camera memory card was used to display the existing photos on a friends TV but I now find the the photos taken AFTER this event will not show as thumbnails or open in any program.
Please help,
Ian