She gave conflicting evidence over when she took the photos, but as far as I know, she didn't initially deny she took the photos. (I will double-check this) But her initial testimony to the FBI closely matches what she told the WC several months later. She later said that the photos were taken a bit later (not late Feb- early Mar 1963 as she told the FBI/WC, but late Mar/early Apr), which fits in with other evidence. Most importantly, she maintains to this day - even as she now thinks her husband was not responsible for the assassination - that she indeed took the photos. So this suggestion of "government pressure" to make her "change her story" doesn't add up. Why change her belief from "he's guilty" to "he's innocent" (which surely goes against what "the government" would want her to say), while sticking to her "I took the photos" claim? The link has evidence from one Jack White who, to put it charitably, doesn't know what he is talking about. Here is a good link for the HSCA investigation of this issue.