Problems speed slideshow Kodi 17.x

When viewing a slideshow of pictures in Kodi17.x it takes a long time to change photo’s.
More than 20 seconds even if the delay time is set for 1 second.
The pictures are no bigger than 200 kb and be loaded from a USB stick.
The maximum resolution is 1500×1000, JPG type.
In Kodi Jarvis it works okay.

I use a Raspberry Pi 1B +. What could be the cause?