Speed up Picture Slideshow on KDL-52W5500

As the title says is there any way to speed up the slideshow rate on the Sony KDL-52W5500 tv. I have tried the options setting on the TV and it is set to fast but the pictures seem to change only every 3 or 4 minutes. Nearly all the pictures are taken with an 8 Mpixel or 12 Mpixel camera and vary between 1.5Mb to 4.5mb in size. Is this a limitation of the TV or are there any tweaks in Serviio I can make.
Secondly how do I select the root folder of My Pictures for the slideshow. My picture library has seperate subfolders with the event and date. I can sucessfully select a sub folder but not the root My Pictures so that the slideshow picks pictures from every folder. It may be the way I have set up the monitored folders but I am not sure.
Any help would be appreciated
Fozzie

Hi There,
Can anyone help me with this?

[Illico]

For SlideShow, select a folder or image on Sony menu, press [OPTIONS] button, select [Playback Options], [Slideshow Speed], select Fast, Medium or Slow.

For Picture frame, you can not change the period.

Thanks Illico but as per first post I have already selected Fast in the TV Slideshow options menu.
Is this a limitation of the TV or size of the photographs how long the photo displays or are there any tweaks in Serviio which serve up the pictures faster?
Fozzie