Say I have this html code (replace x and y with actual numbers):
<html>
<head>
<style>
IMG {width: 100%;height: auto; max-width:xpx; max-height:ypx;}
</style>
</head>
<body>
<img src="image.jpg" width=x height=y>
</body>
</html>
It automatically sizes the image based on the user's screen size if the screen size is smaller than x by y pixels. Would google's bot recognize the css and believe I'm sizing the image properly or does it not have enough intelligence to do that and just downright assume the image is x by y pixels no matter what?
I'm asking because I don't want to run into any penalties about width being too large especially on my mobile site.