This is an utterly fascinating statement made by a major newspaper outlet:
The photos [of the ailing Castro] were credited to Estudios Revolución, a division of Castro's personal support group that collects historic documents and images. There was no reason to doubt they were real.
Let's take this from another perspective. A mock situation can be conjured up: George W. Bush realeased photos of Weapons of Mass Destruction found in Baghdad earlier today. The photos were credited to Bush Productions, a division of Bush's personal campaign office. There was no reason to doubt they were real.
Look, I'm sorry, but any images (especially photos) coming from a group personally attached to Castro-- not to mention that it's in a communist country where every aspect of public life and media are carefully controlled-- are automatically doubted as to their authenticity.