Canvas: 400 × 300 px
This placeholder image generator is straightforward to use. Here is a step-by-step guide:
Select a Size: Choose from the preset size buttons above for common specs, including standard ad slot dimensions (e.g., 300×250, 728×90), screen resolutions (e.g., 1920×1080, 1280×720), and general testing sizes. Clicking any preset automatically fills the width and height fields. You can also enter custom values directly (range 1-4096 pixels).
Set Colors: Click preset color swatches to quickly switch background or text colors. For precise control, use the custom color picker to enter any hex color value. Ensure sufficient contrast between background and text for readability.
Adjust Text: Enter your desired text in the Text field. If left empty, the tool will display the image dimensions (e.g., "400 × 300"). Use the Font Size slider to adjust text size (8-120px), and the Corner Radius slider to add rounded corners (0-100px).
Download: The live preview updates instantly as you adjust settings. Click the "Download PNG" button to save the generated placeholder to your device for use in your projects.
Placeholder images are widely used in web development and UI design. Here are some typical scenarios:
Frontend Development: When building product listings, galleries, or article cover pages, the backend API may not yet return real image data. Placeholder images keep the layout intact during development, preventing layout breaks caused by missing images. Developers can generate placeholders matching the exact dimensions from the design specs.
UI/UX Design Prototyping: Designers often need to fill image areas when creating high-fidelity prototypes. Placeholder images help quickly populate content areas, allowing clients and team members to visualize the final product without waiting for actual assets.
Ad Slot Testing: In ad system development, different ad slots have strict size requirements (e.g., Google AdSense 728×90 leaderboard, 300×250 medium rectangle). Using correctly sized placeholders helps developers debug responsive layouts and ad container adaptive logic.
What is a Placeholder Image? A placeholder image is a temporary visual used when final content is not yet available. Its primary purpose is to maintain page layout stability and enable parallel development and design workflows without being blocked by asset preparation. Professional placeholders typically include clear size indicators so team members can quickly identify the intended dimensions.
Common Ad Slot Size Standards: The Interactive Advertising Bureau (IAB) defines globally recognized ad size standards. The most common include: 300×250 (medium rectangle, most popular), 728×90 (leaderboard), 160×600 (wide skyscraper), 320×50 (mobile banner), and 970×90 (large leaderboard). Knowing these standards helps generate placeholders that match industry norms.
Canvas API and Image Generation: This tool is built on the HTML5 Canvas API, which runs entirely in the browser. Canvas provides pixel-level drawing control, including fill colors, text rendering, and rounded rectangles. Using canvas.toDataURL('image/png'), the canvas content can be exported as a PNG Data URL, enabling pure frontend image generation without any backend service.
Currently supports PNG download. PNG supports transparency and lossless compression, making it ideal for web development and design prototyping. JPG and WebP formats may be added in future versions.
Yes. The placeholder images generated by this tool are pure solid-color backgrounds with text, containing no copyrighted material. You are free to use them for commercial projects, personal projects, or any purpose.
Due to browser Canvas API limitations, it is recommended to keep dimensions under 4096×4096 pixels. Exceeding this may cause the canvas to fail to create or degrade browser performance. Most development scenarios (ad slots, product images, avatars, etc.) are well below this limit.
When the image size is small, the default font size may exceed the canvas display area. Please reduce the font size or shorten the text content. The tool automatically checks if text fits within the canvas and gives a hint when it overflows.
No. This tool runs entirely in your browser using the HTML5 Canvas API to generate images locally. All input data including dimensions, colors, and text never leaves your device. There are no privacy concerns.
Currently, images need to be generated and downloaded one at a time. You can click different preset size buttons in sequence and download each separately. Batch generation and zip download may be added in future versions.
Currently, transparent backgrounds are not supported. All generated placeholders have solid-color backgrounds. If you need transparent placeholders, you can use image editing software (such as Photoshop or GIMP) to remove the background from the downloaded PNG, or use a dedicated transparent image generator.
Yes, non-Latin characters such as Chinese, Japanese, Korean, and Emoji are supported. The Canvas will use the system default fonts. If the device has the corresponding font installed, the characters will render correctly.