diff --git a/.vscode/launch.json b/.vscode/launch.json
new file mode 100644
index 0000000..a3ba8c3
--- /dev/null
+++ b/.vscode/launch.json
@@ -0,0 +1,21 @@
+{
+  "version": "0.2.0",
+  "configurations": [
+    {
+      "name": "Launch Chrome against localhost, with sourcemaps",
+      "type": "chrome",
+      "request": "launch",
+      "url": "http://localhost:8001",
+      "sourceMaps": true,
+      "webRoot": "${workspaceRoot}"
+    },
+    {
+      "name": "Attach to Chrome, with sourcemaps",
+      "type": "chrome",
+      "request": "attach",
+      "port": 9222,
+      "sourceMaps": true,
+      "webRoot": "${workspaceRoot}"
+    }
+  ]
+}
\ No newline at end of file
diff --git a/demo/images/tibet-6.jpg b/demo/images/tibet-6.jpg
new file mode 100644
index 0000000..126f480
Binary files /dev/null and b/demo/images/tibet-6.jpg differ
diff --git a/demo/index.tsx b/demo/index.tsx
index 37f9415..4fc9f36 100644
--- a/demo/index.tsx
+++ b/demo/index.tsx
@@ -1,15 +1,16 @@
 import * as React from 'react';
 import * as ReactDOM from 'react-dom';
 import ViewerWrap from '../src/ViewerWrap';
-const imgSrc2 = require('./images/landscape2.jpg');
-const imgSrc = require('./images/landscape.jpg');
+const img2 = require('./images/landscape2.jpg');
+const img = require('./images/landscape.jpg');
+const img3 = require('./images/tibet-6.jpg');
 
 class App extends React.Component<any, any> {
   constructor() {
     super();
 
     this.state = {
-      visible: true,
+      visible: false,
     };
   }
 
@@ -20,7 +21,7 @@ class App extends React.Component<any, any> {
         <ViewerWrap
         visible={this.state.visible}
         onClose={() => { this.setState({ visible: false }); } }
-        images={[imgSrc, imgSrc2]}
+        images={[img2, img, img3]}
         />
       </div>
     );
diff --git a/package.json b/package.json
index 28a777b..abc4531 100644
--- a/package.json
+++ b/package.json
@@ -27,7 +27,6 @@
     "@types/react": "^0.14.39",
     "@types/react-dom": "^0.14.17",
     "atool-build": "^0.8.1",
-    "classnames": "^2.2.5",
     "dora": "^0.4.3",
     "dora-plugin-browser-history": "^0.2.0",
     "dora-plugin-webpack": "^0.8.1",
diff --git a/src/Viewer.tsx b/src/Viewer.tsx
index 3d42294..9d757d0 100644
--- a/src/Viewer.tsx
+++ b/src/Viewer.tsx
@@ -1,11 +1,12 @@
 import * as React from 'react';
 import './style/index.less';
-import ViewerFooter from './ViewerFooter';
+import ViewerCore from './ViewerCore';
+import ViewerNav from './ViewerNav';
 
 function noop() {}
 
 interface ViewerState {
-  activeIndex: number;
+  activeIndex?: number;
 }
 
 export default class Viewer extends React.Component<ViewerProps, ViewerState> {
@@ -13,36 +14,64 @@ export default class Viewer extends React.Component<ViewerProps, ViewerState> {
     visible: false,
     onClose: noop,
     images: [],
+    activeIndex: 0,
   };
 
   private prefixCls: string;
 
-  constructor() {
-    super();
+  constructor(props) {
+    super(props);
 
     this.prefixCls = 'react-viewer';
 
     this.state = {
-      activeIndex: 0,
+      activeIndex: this.props.activeIndex,
     };
+
+    this.handleChangeImg = this.handleChangeImg.bind(this);
   }
 
   handleClose(e) {
     this.props.onClose();
   }
 
+  handleChangeImg(newIndex: number) {
+    let newState = this.state;
+    newState.activeIndex = newIndex;
+    this.setState(newState);
+  }
+
+  componentWillReceiveProps(nextProps: ViewerProps) {
+    if (this.state.activeIndex !== nextProps.activeIndex) {
+      this.setState({
+        activeIndex: nextProps.activeIndex,
+      });
+    }
+  }
+
   render() {
+    let activeImgSrc = '';
+    if (this.props.images.length > 0) {
+      activeImgSrc = this.props.images[this.state.activeIndex];
+    }
+
     return (
       <div style={{display: this.props.visible ? 'block' : 'none'}}>
         <div className={`${this.prefixCls}-mask`}></div>
         <div className={`${this.prefixCls}-close`} onClick={this.handleClose.bind(this)}></div>
-        <div className={`${this.prefixCls}-container`}>
-        </div>
-        <ViewerFooter
+        <ViewerCore
         prefixCls={this.prefixCls}
-        images={this.props.images}
-        activeIndex={this.state.activeIndex}
+        imgSrc={activeImgSrc}
+        visible={this.props.visible}
         />
+        <div className={`${this.prefixCls}-footer`}>
+          <ViewerNav
+          prefixCls={this.prefixCls}
+          images={this.props.images}
+          activeIndex={this.state.activeIndex}
+          onChangeImg={this.handleChangeImg}
+          />
+        </div>
       </div>
     );
   }
diff --git a/src/ViewerCore.tsx b/src/ViewerCore.tsx
new file mode 100644
index 0000000..c8c35c7
--- /dev/null
+++ b/src/ViewerCore.tsx
@@ -0,0 +1,169 @@
+import * as React from 'react';
+
+export interface ViewerCoreProps {
+  prefixCls: string;
+  imgSrc: string;
+  visible: boolean;
+}
+
+interface ViewerCoreState {
+  width?: number;
+  top?: number;
+  left?: number;
+  isMouseDown?: boolean;
+  mouseX?: number;
+  mouseY?: number;
+}
+
+export default class ViewerCore extends React.Component<ViewerCoreProps, ViewerCoreState> {
+
+  constructor() {
+    super();
+
+    this.state = {
+      width: 0,
+      top: 15,
+      left: null,
+      isMouseDown: false,
+      mouseX: 0,
+      mouseY: 0,
+    };
+
+    this.handleMouseScroll = this.handleMouseScroll.bind(this);
+    this.handleMouseDown = this.handleMouseDown.bind(this);
+    this.bindEvent = this.bindEvent.bind(this);
+    this.handleMouseMove = this.handleMouseMove.bind(this);
+    this.handleMouseUp = this.handleMouseUp.bind(this);
+    this.handleResize = this.handleResize.bind(this);
+  }
+
+  componentDidMount() {
+    this.bindEvent();
+    this.resizeImg(this.props.imgSrc);
+  }
+
+  resizeImg(imgSrc) {
+    let img = new Image();
+    img.src = imgSrc;
+    img.onload = () => {
+      let width = 0;
+      let height = 0;
+      let imgWidth = img.width;
+      let imgHeight = img.height;
+      let aspectRatio = imgWidth / imgHeight;
+      if (aspectRatio > 1) {
+        width = Math.min(window.innerWidth * .9, imgWidth);
+        height = (width / imgWidth) * imgHeight;
+      }else {
+        height = Math.min((window.innerHeight - 52) * .8, imgHeight);
+        width = (height / imgHeight) * imgWidth;
+      }
+      let left = ( window.innerWidth - width ) / 2;
+      let top = (window.innerHeight - height) / 2;
+      this.setState({
+        width: width,
+        left: left,
+        top: top,
+      });
+    };
+  }
+
+  handleResize(e) {
+    this.resizeImg(this.props.imgSrc);
+  }
+
+  handleMouseDown(e) {
+    e.preventDefault();
+    e.stopPropagation();
+    this.setState({
+      isMouseDown: true,
+      mouseX: e.nativeEvent.pageX,
+      mouseY: e.nativeEvent.pageY,
+    });
+  }
+
+  handleMouseMove(e) {
+    if (this.state.isMouseDown) {
+      let diffX = e.x - this.state.mouseX;
+      let diffY = e.y - this.state.mouseY;
+      this.setState({
+        top: this.state.top + diffY,
+        left: this.state.left + diffX,
+        mouseX: e.x,
+        mouseY: e.y,
+      });
+    }
+  }
+
+  handleMouseUp(e) {
+    this.setState({
+      isMouseDown: false,
+    });
+  }
+
+  handleMouseScroll(e) {
+    let direct: 0 | 1 | -1 = 0;
+    if (e.wheelDelta) {
+      direct = e.wheelDelta > 0 ? 1 : -1;
+    }else if (e.detail) {
+      direct = e.detail > 0 ? 1 : -1;
+    }
+    if (direct !== 0) {
+      this.setState({
+        width: this.state.width + direct * this.state.width * 0.05,
+      });
+    }
+  }
+
+  bindEvent(remove?: boolean) {
+    let funcName = 'addEventListener';
+    if (remove) {
+      funcName = 'removeEventListener';
+    }
+    document[funcName]('mousewheel', this.handleMouseScroll, false);
+    document[funcName]('click', this.handleMouseUp, false);
+    document[funcName]('mousemove', this.handleMouseMove, false);
+    window[funcName]('resize', this.handleResize, false);
+  }
+
+  componentWillReceiveProps(nextProps: ViewerCoreProps) {
+    if (this.props.imgSrc !== nextProps.imgSrc) {
+      this.resizeImg(nextProps.imgSrc);
+    }
+    if (!this.props.visible && nextProps.visible) {
+      this.bindEvent();
+      this.resizeImg(this.props.imgSrc);
+    }
+    if (this.props.visible && !nextProps.visible) {
+      this.bindEvent(true);
+    }
+  }
+
+  render() {
+    let imgStyle: React.CSSProperties = {
+      width: `${this.state.width}px`,
+      marginTop: `${this.state.top}px`,
+      marginLeft: this.state.left ? `${this.state.left}px` : 'auto',
+    };
+
+    let imgClass = '';
+    if (!this.state.isMouseDown) {
+      imgClass = `${this.props.prefixCls}-transition`;
+    }
+
+    return (
+      <div
+      className={`${this.props.prefixCls}-core`}
+      onMouseDown={this.handleMouseDown}
+      >
+        <img
+        ref="img"
+        className={imgClass}
+        src={this.props.imgSrc}
+        style={imgStyle}
+        onMouseDown={this.handleMouseDown}
+        />
+      </div>
+    );
+  }
+}
diff --git a/src/ViewerFooter.tsx b/src/ViewerFooter.tsx
deleted file mode 100644
index 0d0434a..0000000
--- a/src/ViewerFooter.tsx
+++ /dev/null
@@ -1,22 +0,0 @@
-import * as React from 'react';
-import ViewerNav from './ViewerNav';
-
-export interface ViewerFooterProps {
-  prefixCls: string;
-  images: any[];
-  activeIndex: number;
-}
-
-export default class ViewerFooter extends React.Component<ViewerFooterProps, any> {
-  render() {
-    return (
-      <div className={`${this.props.prefixCls}-footer`}>
-        <ViewerNav
-        prefixCls={this.props.prefixCls}
-        images={this.props.images}
-        activeIndex={this.props.activeIndex}
-        />
-      </div>
-    );
-  }
-}
diff --git a/src/ViewerNav.tsx b/src/ViewerNav.tsx
index daa1db6..ad8563c 100644
--- a/src/ViewerNav.tsx
+++ b/src/ViewerNav.tsx
@@ -4,6 +4,7 @@ export interface ViewerNavProps {
   prefixCls: string;
   images: any[];
   activeIndex: number;
+  onChangeImg: (index: number) => void;
 }
 
 export default class ViewerNav extends React.Component<ViewerNavProps, any> {
@@ -11,12 +12,22 @@ export default class ViewerNav extends React.Component<ViewerNavProps, any> {
     activeIndex: 0,
   };
 
+  handleChangeImg(newIndex) {
+    this.props.onChangeImg(newIndex);
+  }
+
   render() {
     return (
       <div className={`${this.props.prefixCls}-navbar`}>
         <ul className={`${this.props.prefixCls}-list`}>
           {this.props.images.map((item, index) =>
-            <li className={index === this.props.activeIndex ? 'active' : ''}><img src={item} /></li>
+            <li
+            key={index}
+            className={index === this.props.activeIndex ? 'active' : ''}
+            onClick={this.handleChangeImg.bind(this, index)}
+            >
+              <img src={item} />
+            </li>
             )
           }
         </ul>
diff --git a/src/ViewerProps.ts b/src/ViewerProps.ts
index d2d43a9..58e9d0b 100644
--- a/src/ViewerProps.ts
+++ b/src/ViewerProps.ts
@@ -5,4 +5,6 @@ interface ViewerProps {
   onClose?: () => void;
   /** 需要进行浏览的图片地址集合 */
   images?: any[];
+  /** 当前图像index */
+  activeIndex?: number;
 }
diff --git a/src/style/index.less b/src/style/index.less
index 379e6fb..f227a79 100644
--- a/src/style/index.less
+++ b/src/style/index.less
@@ -29,12 +29,22 @@
     z-index: @zIndex;
   }
 
-  &-container {
+  &-core {
     position: absolute;
     top: 0;
     right: 0;
     left: 0;
     bottom: 0;
+    overflow: hidden;
+  }
+
+  &-core > img {
+    display: block;
+    margin: 15px auto;
+    width: auto;
+    height: auto;
+    cursor: move;
+    user-select: none;
   }
 
   &-footer {
@@ -83,4 +93,8 @@
   &-list > li.active > img {
     opacity: 1;
   }
+
+  &-transition {
+    transition: all .3s ease-out;
+  }
 }
\ No newline at end of file