I would not say the photos were neccessarily tampered with. We are looking at 2 video frames, possibly cropped and enlarged. In addition, if you estimate the movements necessary to transfer the individual from position A to position B, you may get to approximately 0.5 seconds. That's my estimation.
Now, the frames look a bit different from each other and LE said that's the best they have. I am going to add "for now". IMO they were in a hurry getting the images out.
Here is why: Certain algorithms are being used to encode a video. Every 0.5 seconds or so a so called 'key frame" is being inserted into the stream. A key frame has all its pixels recreated/transferred in the encoded stream while still showing some loss of quality due to compression. The not so good frames simply do not have all their pixels recreated/transferred esp. if the bit rate is too low. So, adjusting the bitrate and a better algorithm for the decoding process will generate better results IMO.
I am not very adapt at working with moving images, so perhaps someone else can chime in. It looks like we do not have a key frame ( therefore the two frames are just under 0.5 secs apart ) or we do have a key frame, but due to additional movements -like shaking the camera for example- the frame lost quality ( therefore the two frames would be just about 0.5 secs apart). Something like that.
All IMO
-Nin