How would you remove the styling from some images in the Bistro theme?

When you insert a picture into your post you will get something like the following:

<img src="" alt="img" width="300" height="200" class="alignleft size-medium wp-image-456" />

first you need to click on the text editor tab so you can add an additional class to the image in my example i’ll add a “no-image-styling” class:

<img src="http://localhost:8888/cafe/wp-content/uploads/2013/01/skulls-300x200.jpg" alt="skulls" width="300" height="200" class="alignleft size-medium wp-image-456 no-image-styling" />

then you need to go to the style.css file and add the following on the last line:

background: transparent !important;
border: none !important;

Any image that you wish to remove styling now you can just add a class of no-image-styling.