Features
Image canvas extender
Add transparent or coloured padding to any side of an image to hit an aspect ratio without cropping the subject.
What it does
The canvas extender places your image on a larger canvas, adding padding on the sides or top/bottom to reach a target aspect ratio. Unlike cropping, nothing is removed from your original image — only extra canvas is added.
This is the correct approach when:
- You need to post a portrait photo to a platform that requires landscape (or vice versa)
- Your image has content too close to the edges to safely crop
- You want to create a border or margin effect
- You're preparing images for print formats that differ from your camera's native aspect ratio
Aspect ratio presets
| Preset | Use case |
|---|---|
| 1:1 Square | Instagram feed, profile thumbnails |
| 4:3 Classic | Standard displays, presentations |
| 16:9 Widescreen | YouTube, most monitors, modern TV |
| 9:16 Vertical | Instagram Stories, TikTok, Reels |
| 4:5 Instagram | Instagram portrait feed posts (tallest allowed non-story) |
| 21:9 Cinematic | Ultrawide displays, cinematic letterbox |
| Custom | Enter any width and height ratio |
Padding color
Choose any color for the added canvas area using the color picker. Quick access buttons for White and Black are provided. The default is black — matching most cinematic and professional conventions.
For a seamless-looking result, try sampling a color from the edge of your image and entering it as the padding color.
How the target canvas is calculated
Given a source image and a target aspect ratio, the tool calculates the minimum canvas size that:
- Fits the source image at its original pixel dimensions
- Achieves the target aspect ratio exactly
If your source image is wider than the target ratio, padding is added above and below (letterboxing). If your source is taller, padding is added left and right (pillarboxing).
Output format
The extended image is exported as a PNG to preserve the padding color accurately. If your source image was a JPEG, be aware that PNG is losslessly encoded — your image quality is preserved but the file size may be larger.
Limitations
- The source image must be under ~150 MB
- Maximum output canvas is limited by available browser memory (typically 16384 × 16384 px on modern browsers)