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A black iPad Mini rests on a notebook filled with technical drawings. To iPad is tilted to the far right over the notebook, lying next to it is a metal mechanical pencil. To the top you see the beginnings of a keyboard. The iPad Mini will hold an image of 768x1024px in portrait view. Your mockup would be perfect here if it is for a design or sketch app.
Drag & drop not supported, but you can still upload via this input field: