You are incorrect, there are two different games (we own both). The images are wrong for Boggle Jr. Letters.
I'll gladly be corrected if it brings me to the truth!
But I'm not sure how the two games are different.
This is the Boggle Jr Letters:
But this Boggle Junior game also has a timer and looks identical:
So if you look closely at the box art above, these two boxes show the same game - the picture cards, letter tiles, timer etc appear to be identical. I have the Boggle Junior game pictured above, and can confirm that it is identical to what I see on the box art of the Boggle Jr Letters game.
If you ask me, it seems like one game marketed with two different names ("Boggle Junior" and "Boggle Jr Letters"), no?