Expandable padded mailer

A padded mailer, comprising:

• a pouch formed by front and rear sheets, wherein each sheet includes a bottom edge, a top edge, and opposing side edges, wherein the sheets are connected along their respective bottom edges and along each of their respective opposing side edges to define an interior space, wherein a direction from the bottom edges to the top edges is a bottom-to-top direction, and wherein the top edges of the sheets are unconnected to form an opening into the interior space;
• and
• a liner disposed in the interior space, the liner including at least one expandable sheet that includes a bottom edge, a top edge, and opposing side edges, wherein the bottom edge of the expandable sheet is secured to at least one of the front and rear sheets adjacent their respective bottom edges, and the top edge and the opposing side edges of the expandable sheet are unsecured to the front and rear sheets such that the expandable sheet is free to expand in the bottom-to-top direction relative to the pouch;
• wherein pulling the top edge of the expandable sheet in the bottom-to-top direction relative to the pouch causes the expandable sheet to expand and increase the thickness of the liner.