My images in posts from my desktop theme are to...

In style.css try adding some css to your images:

p > img { max-width:100% !important; height:auto !important; }

...or with a class:

img.size-full { max-width:100%; height:auto !important; }

...or if image is a link:

a > img { max-width:100% !important; height:auto !important; }