How to Generate Placeholder Images

3 min read by Mohammad Shoeb

How to Generate Placeholder Images

Placeholder images are sized dummy graphics you drop into a layout while the real photos and graphics are still being made. They let you build mockups, prototypes, responsive grids, and CMS demos without waiting on assets. The fastest way to make one is to set the width, height, and label, then export a PNG. Here is how.

Why use placeholder images

When you are building a layout, the slots for images are often empty long before the real artwork exists. Dropping in correctly sized placeholders gives you several wins at once:

  • No layout shift. A box at the exact final dimensions reserves the right space, so the page does not jump when real images arrive.
  • Faster reviews. Stakeholders see a realistic layout instead of empty gaps or broken-image icons.
  • Clear specs. A placeholder labeled with its own size doubles as a note to whoever delivers the final asset.

Generating them locally also means you avoid hammering a third-party placeholder service on every page load, and your in-progress layout dimensions never leave your machine.

Generate a placeholder image in five steps

  1. Open the Image Placeholder Generator.
  2. Set the exact width and height in pixels to match the slot in your layout, for example 1200 by 630 for a social card or 400 by 400 for a thumbnail.
  3. Choose a background color and text color so the placeholder reads clearly against your design.
  4. Add a label. A common choice is the dimensions themselves (like “1200 x 630”) so the size is visible at a glance.
  5. Export as PNG and drop the file into your project.

The whole thing runs in your browser. Nothing is uploaded, so it works offline and keeps your design private.

Pick dimensions that prevent layout shift

The single most useful habit is to size placeholders to the real final dimensions. If a hero image will ship at 1600 by 900, generate the placeholder at 1600 by 900, not at some rounder guess. When the browser knows the correct box size up front, content below it does not get pushed around when the real file loads. That keeps your Cumulative Layout Shift score low and makes the in-progress page feel finished.

If you are working with responsive grids, generate one placeholder per breakpoint size and swap them as you test. Labeling each with its size makes it obvious which is which.

Color and labeling tips

Use muted, neutral backgrounds so placeholders do not compete with real UI for attention. A light gray box with darker gray text reads as “pending asset” without distracting reviewers. Reserve bolder colors when you want to flag a specific slot for discussion.

For the label, the dimensions are the most practical default, but you can also write the asset’s purpose (“Author headshot” or “Product shot”) so the design doubles as a brief. When you are happy with the look, head back to the Image Placeholder Generator and export each variant you need as a PNG.

Set the size, label it, export a PNG, and your layout holds its shape until the real assets land.

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