Function setPreviewImageSize

setPreviewImageSize(size): void
JMap.MapContext.setPreviewImageSize

Set the preview image size, by default size is :
- Width: 100
- Height: 100
Parameters
- size: JSize
  preview image size
Returns void
Throws
if given size is not an object having positive and greater than zero width and height

Example
```
// set the review image size
JMap.MapContext.setPreviewImageSize({
 width: 100,
 height: 200
})
```