Responsive Banner Slide - transparent background renders red

Just implementing the Responsive Banner Slide on our site. Lots to like, but there are niggling issues.

The main one at the moment is that PNG image files have their transparent background rendered red. Also, when a transparent background image file is used in the slider the transition is not at all smooth.

Short of going through hundreds of images and setting a solid background colour, is there a more practical solution?

Thanks

Nevermind. I decided to change the image files to solid colour background and as JPG, to take advantage of the smaller size compared to PNG

Thanks