Hotjar uses snapshots for Heatmaps, Recordings, and Form Analysis. A Snapshot is an on-demand report based on a sample of data. The snapshot size refers to the number of visitors used to generate a particular report.
So for example, if you take a Heatmap snapshot of your homepage, a report is generated based on a number of visitors that visited the page right after the snapshot is created.
Snapshot sizes for Heatmaps depend on your plan. They are as follows: