> The declaration also says that CIA cannot release these TIFF files in electronic form because they can be so easily altered by the mere act of a CIA FOIA analyst looking at them, and that the security measures they must take to remove this accidental metadata for an electronic release (involving editing each file separately by hand) would take 28 years and 1,200 CDs.

Aside from the issue of the CIA apparently not being able to develop (or download) a batch metadata editing tool, a common excuse by agencies for releasing data as PDFs or image files, instead of Excel/CSV, is because the latter is too easy to manipulate by the public:

http://www.nytimes.com/2010/04/13/business/13docpay.html

> Among the four leading drug companies making physician payment disclosures, Mr. Coukell said, Eli Lilly, which was the first to disclose, presents data as an Adobe Flash image, which he said was impossible to download or to sort. “They’ve gone out their way, I think, to present it as a Flash document,” Mr. Coukell said.

> Mr. Dunston said Obsidian had to retype all the Lilly data.

> Carole Puls, a Lilly spokeswoman, said the company purposely made its report impossible to download "to protect the integrity of the data." Lilly was concerned someone could change numbers and create a false report outside the company’s Web site, Ms. Puls said.