ImageMerge | 将多张图片合并成一张图片，可用于生成IM即时通讯群组拼接头像。

As the samples state mergeImages method returns a Promise. So you need to await it to get the actual values like :

As stated in the comments, there are several issues :

1. In your loop, you are overwriting the content of the final image at each iteration, the graphics object of the final image must be declared once, before the loop.
2. You are attempting to write each image at the same coordinates (0,0). If you want to arrange the images vertically, use a variable (yPosition here) to keep track of the current y location .
3. You don't have to create new File, fileEntry is already the File object you want

Putting it all together :

I found the answer myself. It looks like that the DrawImage method was not considering the default size of image. So I had to define their original size in order for successful merging.

I just updated: