I wasn't really satisfied with the screen cap comparison's that have been put up so far (no offense to the people who made them...I just didn't feel like I could make an accurate judgement based on them), so I made one of my own that will hopefully help other confused people. It led me to an interesting conclusion.
Here's the first one:

My conclusion is that these are definitely different pictures, taken at different places, but not necessarily of different people. Of course, the first photo could be the same as one of the other Tach drop photos, just at a different angle. More on why that might be later.
edit: Everyone else thinks it's a road, not a river. I bow to majority opinion.
And the second:

I think these ARE the same picture--or, at least, taken of the same person in the same place at the same time.
Now, I got to thinking, especially about the second picture, because I was puzzled about the difference in the way that the photo was out of focus. I have two thoughts on this. First, I've taken photos with my digital camera where a picture taken with the flash comes out like the DB photo, while the same photo without the flash looks more like the Tachyon drop photo. That's one explanation. The second explanation is that the same picture was taken at the same time, but
by two different people with two different cameras. I find this explanation more interesting, because it seems to connect with the quote "Who watches the watchers?" If two people were taking pictures of Daniel as he was watching the fake ceremony, one was certainly taken by representatives of the Order and is the one that appeared on Lucy's computer. But the other one would have been taken by a third party, who might not only have been watching Daniel, but the other photographer as well. This third photographer would be watching the watcher...who was watching Daniel, who was watching Bree...
Another screen cap from the "Following the Helper" video that we should keep in mind:

This is the picture of the "10-12-06" folder that Daniel opened on Lucy's computer. We can see at the bottom of the screen that at least three files exist in this folder. So even though we only see two photos of Daniel in the video, we know more photos exist...these might explain the photos Tach has. Or they might not. But it's important to keep in mind.
Sorry for excessive length...
"A step in the right direction? It only turns out to be so if you're willing to step much further."
-Samuel R. Delany