Currently thumbnails will be chosen by taking a timestamp and turning that into a thumbnail index by math.flooring it with the thumbnail interval/delta.
This means the thumbnail being displayed is before the position the user would click on, and slightly misleading; the jump will rarely happen on the actual thumbnail timestamp (and overriding the seek would be a pain/detrimental for accurate seeking) but instead after the moment has passed.

This feels "wrong".
How do other players do it? Do they choose their thumbnail timestamps with some clever logic?
What logic do they use to choose which thumbnail to show? Is it a "closest" timestamp, the next thumbnail, or what?
The downside with displaying simply the next thumbnail would be short videos having their thumbnails be almost useless. Maybe move generate timestamps up by half an interval and choose the closest thumbnail?

This is here to allow others to chime in. What are your thoughts?