Resize image in the wiki of GitHub using Markdown

I’m writing a wiki page on GitHub, and I’m using Markdown.

My problem is that I’m putting a large image (this image is in its own repository) and I need resize it.

I have tried different solutions, but they do not work:

![image](http://url.to/image.png "Title" {width=40px height=400px})

![image](http://url.to/image.png = 250x250)

![image](http://url.to/image.png = 250x)

[[http://url.to/image.png = 250x]]

Is there a way to get it?

It is preferable without HTML.