---
id: css-border-images
title: "CSS Border Images"
category: "Frontend"
status: "draft"
verification_status: "conceptual"
canonical_id: ""
aliases: ["border-image", "border-image-source", "border-image-slice", "border-image-repeat", "CSS image border", "nine-slice border"]
duplicate_of: ""
source_trust_level: "B"
confidence_score: 0.88
created_at: 2026-06-23
updated_at: 2026-06-23
review_reason: ""
merge_history: []
tags: ["css", "web", "frontend", "w3schools", "border-image", "borders"]
raw_sources: ["https://www.w3schools.com/css/css3_border_images.asp"]
applied_in: []
github_commit: ""
---

# [[CSS Border Images]]

## 🎯 한 줄 통찰 (One-line insight)
The `border-image` property lets you use an image as the border around an element instead of a normal border, slicing the image into nine sections so corners stay fixed while the sides repeat, round, or stretch. [S1]

## 🧠 핵심 개념 (Core concepts)
- **`border-image`** — defines an image to be used as the border around an element, instead of the normal border. [S1]
- **Nine-slice model** — the image is sliced into nine sections (like a tic-tac-toe board); corners are placed at the corners, and the middle sections are repeated or stretched. [S1]
- **`border` prerequisite** — for `border-image` to work, the element also needs the `border` property set. [S1]
- **Shorthand** — `border-image` is shorthand for `border-image-source`, `border-image-slice`, `border-image-width`, `border-image-outset`, and `border-image-repeat`. [S1]
- **Repeat behaviors** — sides can be repeated, rounded, or stretched. [S1]

## 🧩 추출된 패턴 (Extracted patterns)
- **Slice-and-place pattern** — slice once, then corners pin while edges tile/stretch to fill any border length. [S1]
- **Transparent base border pattern** — examples set a transparent `border` (e.g., `10px solid transparent`) so the image border fills space the regular border reserves. [S1]
- **Slice-value pattern** — the slice value (a unitless number or a percentage like `20%`/`30%`) controls how much of the image becomes corners vs. edges. [S1]

## 📖 세부 내용 (Details)
**CSS `border-image` Property**
The `border-image` property allows you to define an image to be used as the border around an element, instead of the normal border. The image is sliced into nine sections (like a tic-tac-toe board), with the corners placed at the corners and the middle sections repeated or stretched. [S1]

**Note:** For `border-image` to work, the element also needs the `border` property set! [S1]

The `border-image` property is a shorthand for the following: [S1]
- `border-image-source` — defines the path to the image. [S1]
- `border-image-slice` — defines how to slice the image. [S1]
- `border-image-width` — defines the width of the image. [S1]
- `border-image-outset` — defines the amount by which the border image area extends beyond the border box. [S1]
- `border-image-repeat` — defines whether the image is repeated, rounded, or stretched. [S1]

Example — image border with `round`: [S1]
```css
#borderimg {
  border: 10px solid transparent;
  padding: 15px;
  border-image: url(border.png) 30 round;
}
```

Example — image border with `stretch`: [S1]
```css
#borderimg {
  border: 10px solid transparent;
  padding: 15px;
  border-image: url(border.png) 30 stretch;
}
```

Example — different slice values across multiple elements: [S1]
```css
#borderimg1 {
  border: 10px solid transparent;
  padding: 15px;
  border-image: url(border.png) 50 round;
}

#borderimg2 {
  border: 10px solid transparent;
  padding: 15px;
  border-image: url(border.png) 20% round;
}

#borderimg3 {
  border: 10px solid transparent;
  padding: 15px;
  border-image: url(border.png) 30% round;
}
```

**CSS Border Image Properties**

| Property | Description |
|----------|-------------|
| `border-image` | Shorthand for all the border-image-* properties |
| `border-image-source` | Specifies the path to the image used as a border |
| `border-image-slice` | Specifies how to slice the border image |
| `border-image-width` | Specifies the widths of the border image |
| `border-image-outset` | Specifies the amount by which the border image area extends beyond the border box |
| `border-image-repeat` | Specifies whether the border image should be repeated, rounded, or stretched |

[S1]

## 🛠️ 적용 사례 (Applied in summary)
The page's own examples are the applied cases: a single image border with `round` and with `stretch`, plus three elements using different slice values (`50`, `20%`, `30%`). No external project/commit applications found in the source.

## 💻 코드 패턴 (Code patterns)
Basic image border (language: CSS) — note the required transparent `border`:
```css
selector {
  border: 10px solid transparent;
  padding: 15px;
  border-image: url(border.png) 30 round;
}
```
Stretched variant:
```css
selector {
  border: 10px solid transparent;
  padding: 15px;
  border-image: url(border.png) 30 stretch;
}
```

## ⚖️ 모순 및 업데이트 (Contradictions & updates)
No contradictions found in the source.

## ✅ 검증 상태 및 신뢰도
- **상태:** draft
- **검증 단계:** conceptual (실제 적용 사례 발견 시 applied/validated로 승격 가능)
- **출처 신뢰도:** B (W3Schools — widely used educational reference, not a primary standards body)
- **신뢰 점수:** 0.88
- **중복 검사 결과:** 신규 생성 (New discovery)

## 🔗 지식 그래프 (Knowledge Graph)
- **상위/루트:** [[CSS Tutorial]]
- **관련 개념:** [[CSS Rounded Corners]], [[CSS Multiple Backgrounds]], [[CSS Background Size]]
- **참조 맥락:** Referenced when an element needs a decorative or themed border that a solid color cannot provide.

## 📚 출처 (Sources)
- [S1] W3Schools — CSS Border Images — https://www.w3schools.com/css/css3_border_images.asp

## 📝 변경 이력 (Change history)
- 2026-06-23: Initial draft synthesized from the W3Schools "CSS Border Images" page (Astra wiki-curation, P-Reinforce v3.1 format).
