If you create some content pages within your website, you may want to look at making them responsive for mobile sites. To do this, you just need to alter some image properties after you have loaded the image you want to make responsive.
1. Upload your Image as normal
2. In the Image Properties, Unlock the Image Size Area, and Delete the Height
3. Then in the Advanced Tab, under Stylesheet Classes, add the text - img-responsive
Under Style, add the text width:630px (Change the width to whatever YOUR image width is as 630 is our example)
Then click OK
Your image is now responsive. You can check by scaling your browser page down, or checking on a smart phone.