I just installed Launchbox and imported some SNES games and am experiencing the same thing.
For example, My first four games in the list are ActRaiser, ActRaiser 2, Advanced Dungeons & Dragons: Eye of the Beholder, then Aladdin.
- When launching Big Box Mode and bringing up my list of Super NES games, ActRaiser is selected by default. The .mp4 video is playing in the background, the box art is displayed, but there is no screenshot.
- If I move down to ActRaiser 2, the box art and background video changes, but there is still no screenshot.
- If I move down to Advanced Dungeons & Dragons: Eye of the Beholder, the boxart changes, but I now I have a title screenshot.
- Moving down to Aladdin however the box art and background video will change, but the screenshot will stay on the Eye of the Beholder screenshot. Moving back up through the games (EotB, ActRaiser 2, ActRaiser) the Eye of the Beholder screenshot will persist.
It definitely looks like it has something to do with background videos being enabled. As I go through the titles in the library the Eye of the Beholder screenshot will not change until I get to another game that does *not* have a background video. At that point the screenshot will change to the title screen for that game, and then that screenshot will persist until I get to another game without a background video.
The Eye of the Beholder screenshot stayed there until I got to my English translation of Dragon Quest I.II. Then my background switched from the previous listing's video to a static art screenshot, and the title screenshot for Dragon Quest I.II was shown. Next on the list is the English translations for Dragon Quest V and VI, neither of which have videos for the background and both of which updated the title screenshot. Continuing to Earthbound the Dragon Quest VI screenshot remained.
**EDIT**
However, after giving up and disabling the option to show the background video, I believe it's by design. By disabling the background video I see that the default behavior is to play the videos in that spot where the screenshot is non-persistent. I didn't notice this because I'd thought I'd already had the videos downloaded prior to turning on the option to play them in the background. Once I saw it wasn't working I then noticed I didn't actually have the snaps, so I grabbed them and then noticed the above behavior. I realize now that the default intent is to have these snaps playing below the box art, not have a screenshot below the boxart, and that's actually fine with me.