Blank Image Generator
The blank image generator creates a solid-colour image at any size up to 4000 by 4000 pixels and downloads it as PNG, JPG or WebP. The dimensions can be burned into the image, which is what makes a placeholder useful in a layout. You can see at a glance which slot you are looking at.
How it works
The image is drawn on an HTML canvas in your browser and exported with toDataURL. No file is uploaded and no request is made, so the same tool works offline once the page has loaded.
- PNG is lossless and keeps transparency, but is the largest file for a flat colour.
- JPG is smaller but has no transparency, and flat colour is exactly where its artefacts are least visible.
- WebP is smallest of the three and supports transparency, at the cost of older-browser support that is now rarely relevant.
- The size label scales with the image, at one tenth of the shorter side.
Examples
A hero-image placeholder
Size
1600 x 900
Colour
#e2ded6
Format
PNG
Label
Show dimensions
Result
blank-1600x900.png, a grey rectangle with 1600 × 900 printed in the centre
The 16:9 ratio matches a standard hero slot, and the printed dimensions make it obvious which placeholder is which when several are in one layout.
A plain colour swatch
Size
512 x 512
Label
Plain colour only
Format
WebP
Result
blank-512x512.webp, a solid square with no text
Without the label the file is a flat colour, which compresses to a few hundred bytes in WebP.
Frequently asked questions
Why is the maximum size 4000 pixels?
Because canvas dimensions are limited by browser and device memory, and the limits differ between them. Safari on iOS is considerably stricter than desktop Chrome. 4000 by 4000 is 16 million pixels, which stays inside every current limit rather than failing silently on some devices.
Which format should I pick for a placeholder?
PNG if you need transparency or exact colour, WebP for the smallest file, JPG only if something in your pipeline requires it. For a flat colour the difference is a few kilobytes either way, so it rarely matters.
Is the image uploaded anywhere?
No. It is drawn on a canvas in your browser and the download is generated from that canvas directly. The page makes no network requests when you change settings or download.
Can I generate a transparent image?
Not from this tool. It fills the canvas with the colour you choose, so the result is always opaque. For a transparent placeholder, generate at the size you need and delete the fill in an image editor, or use a 1px transparent PNG.