I think someone's already mentioned it, but this one makes me a bit sad:
Here's a club that's been setting records for 7 years, that's just won its fourth Cup in five seasons, just appeared in the Finals for the fifth time in six seasons, been a top-3 team in the League for seven straight seasons, and just gone 16-2 in the playoffs to win it all. (Not only that, but they swept both the League's #1 and #4 teams in the process.)
Paul Coffey is gone, but that just resulted in better team defence, and he was replaced by 21-year-old Craig Simpson, who just finished 2nd NHL in goals and had 12 playoff scores. The top 'veteran' superstars are only 27 years old (Gretzky, Messier, Kurri, Anderson), Fuhr and Geoff Courtnall are 25, Tikkanen 23, Ranford and Simpson 21.
Eight years after this photo, Mark Messier will still score at a 50-goal pace and finish 2nd in Hart voting. Six years later, Gretzky wins the scoring title. Nine years later, Fuhr will still be great.
But after this photo (despite the unlikely 1990 Stanley Cup), the Oilers basically become a .500 team for four seasons and then miss the playoffs for four straight years. And -- unbelievably -- after this photo, another 29 years pass before the Oilers have a single .600 season.