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Here is a clean, extra large mockup for your start-up product screenshot. This tabloid poster frame hangs in the portrait position at eye level in the hallway of an executive office building. To the right, around the corner , are grey metal mail boxes #11 and #12. To the left is another hallway and a white, ribbed textured wall. The floor is white and buffed shiny. The screenshot stage is a full 1100 x 1700 px.
Drag & drop not supported, but you can still upload via this input field: