Design a UI for a "Placeholder Image Generator" tool. It should include:
Header: Title "Placeholder Image Generator" and description "Create customized placeholder images by selecting dimensions, icons, background, and icon color."
Inputs for width and height.
Dropdown for icon selection and upload option.
Color pickers for background and icon.
Generate and download buttons.
Preview area for the generated image.
Ensure the UI is responsive and user-friendly. | A shadcn/ui and v0 generation - v0
