Which of the following is a correct action associated with the command for the timeline size?

Zooming into the timeline is the correct action associated with the command for timeline size. This action allows users to adjust the view of the timeline to see more detail in their project, making it easier to edit clips, add transitions, or navigate through the project.

When a user zooms into the timeline, they can precisely work on individual clips and ensure that edits reflect the desired timing and arrangement. This functionality is crucial for fine-tuning projects, as it provides a more granular perspective on the elements within the timeline.

Other options, while relevant to project management and editing, do not specifically pertain to adjusting the timeline size. For instance, minimizing the project refers to reducing the overall interface of the editing software, which does not change how the timeline is presented. Adding new clips involves inserting additional media into the timeline but does not affect its scale. Changing the playback speed impacts how fast the project plays but does not influence the visual representation of the timeline itself.