Previously you'd have to drag the image itself, dragging outside of the image but within the preview tile (e.g. the name) would not start dragging the file, but trigger border select. This often conflicts with user expectations, especially when doing things fast. In fact I've seen many people get annoyed by this, or people have complained about it.
Or explained visually:
| Old | New |
|---|---|
This specific patch sets the "drag hit-box" as indicated here:
That is opposed to using the full tile size: Reason being that the latter leaves quite little space in-between tiles to start dragging a boundbox from.

