There already has been quite the debate about whether it was necessary for the Creators to do this alteration. Many thought it did not do much harm by adding that one still frame. However, some thought it was an effort to draw fans in through deception. I believe that it really didn't harm anything and was alright as long as they do not make habit out of altering vids to the extreme. They mainly did it IMO to:
1) draw focus to this one vid because it was a crucial moment in the series.
2) to attract new viewers at the same time by using a better thumbnail shot.
Having Daniel explain in a message why this was done helped a lot too i think. If there wasn't a message then it would have been a poor decision. Anyways lets not get a heated deal going again though..

LLP is in the house fo rizzle.
Lonelygirl15: "Time for another episode of p-r-o-v-i-n-g s-c-i-e-n-c-e wronngggg!"
Capt. Picard: "Tea Earl Grey, hot"