[Theme: ProReview] – css help, image not updating

I am using the ProReview theme which displays featured ribbons on the home page on each review box. I wanted a ribbon saying “lowest price” which isn’t included so I made my own titled it popular.png and uploaded it to my image files to replace the original popular.png ribbon. However despite the fact I replaced the original image it isn’t displaying on my site. It is still displaying the old ribbon. Can anyone help with this? https://www.hideipprograms.com