Pictures are not responsive

Pictures are not responsive. What would cause the pictures to not be responsive. When I go to my mobile site the pictures are too large. They are also not responsive when screen size changes on my desk top. Thanks for the help in advance

Hi
Please give me your url to check this
CEd

www.urbanlight.org

you have given a fixed height of 500px, you must set the height in % if you want to keep the image ratio and let the slideshow adapts the height also

so what do I put in instead of the 500

your image ratio, like 45%