Slideshow very slow after upgrade to v.17

Dear all,
this is my first post on this community forum, so apologies if I have done something wrong.

I have kodi version 17.3 installed on Raspberry Pi 3 with Raspbian.
After upgrade to 17.3 from version 16, I am facing a problem when using picture slide show.
With version 16 the slide show worked fine even with pan and zooming animations, after the upgrade instead the slide show is very slow and nothing change if I change the time interval between pictures.
The image fading is slow and if I turn on the pan/zoom it is so slow that it can barely be noted.

On a side note, soon after upgrading I had to increase the amount of memory dedicated to graphic acceleration to 128MB in order to be able to see the pictures in the first place. Again strange if we think that with version 16 this was not necessary.

I also tried to solve the slide show problem increasing even further the memory of the graphic board (up to 512MB) with no effect.

Here after the log in debug mode during the slide show:

Code:
18:05:19.872 T:1946088096   DEBUG: Image /home/pi/Immagini/Palermo-Napoli 2017/DSC_0383.JPG is finished rendering, switching to /home/pi/Immagini/Palermo-Napoli 2017/DSC_0386.JPG
18:05:19.873 T:1946080176   DEBUG: CAnnouncementManager - Announcement: OnPlay from xbmc
18:05:19.874 T:1946080176   DEBUG: GOT ANNOUNCEMENT, type: 1, from xbmc, message OnPlay
18:05:19.874 T:1946088096    INFO:   msg: ExifParse: incorrect Exif header
18:05:20.001 T:1946088096   DEBUG: Loading the next image 7: /home/pi/Immagini/Palermo-Napoli 2017/DSC_0387.JPG
18:05:20.204 T:1723012016   DEBUG: COMXCoreComponent::Initialize OMX.broadcom.image_decode input port 320 output port 321 m_handle 0x71064720
18:05:20.205 T:1723012016   DEBUG: COMXCoreComponent::AllocInputBuffers component(OMX.broadcom.image_decode) - port(320), nBufferCountMin(2), nBufferCountActual(2), nBufferSize(7375328), nBufferAlignmen(16)
18:05:20.254 T:1723012016   DEBUG: COMXCoreComponent::Initialize OMX.broadcom.resize input port 60 output port 61 m_handle 0x71039628
18:05:20.255 T:1723012016   DEBUG: COMXCoreComponent::Initialize OMX.broadcom.egl_render input port 220 output port 221 m_handle 0x710263d8
18:05:20.257 T:1723012016   DEBUG: COMXCoreComponent::UseEGLImage component(OMX.broadcom.egl_render) - port(221), nBufferCountMin(1), nBufferCountActual(1), nBufferSize(15360) nBufferAlignmen(16)
18:05:21.289 T:1849680816   ERROR: COMXCoreComponent::DecoderEventHandler OMX.broadcom.image_decode - OMX_ErrorStreamCorrupt, Bitstream corrupt
18:05:21.298 T:1723012016   ERROR: COMXCoreComponent::FreeInputBuffers WaitForCommand:OMX_CommandPortDisable failed on OMX.broadcom.image_decode omx_err(0x8000100b)
18:05:21.300 T:1723012016   DEBUG: COMXCoreComponent::Deinitialize : OMX.broadcom.image_decode handle 0x71064720
18:05:21.302 T:1723012016   DEBUG: COMXCoreComponent::Deinitialize : OMX.broadcom.resize handle 0x71039628
18:05:21.304 T:1723012016   DEBUG: COMXCoreComponent::Deinitialize : OMX.broadcom.egl_render handle 0x710263d8
18:05:21.305 T:1723012016   DEBUG: DecodeJpegToTexture: decoded /home/pi/Immagini/Palermo-Napoli 2017/DSC_0387.JPG 1619x1080
18:05:21.309 T:1723012016   DEBUG: Finished background loading slot 1, 7: /home/pi/Immagini/Palermo-Napoli 2017/DSC_0387.JPG
18:05:21.374 T:1575584688   DEBUG: CWebServer[8080]: request received for /image/image:%2F%2F%252fhome%252fpi%252fImmagini%252fPalermo-Napoli%25202017%252fDSC_0386.JPG%2Ftransform%3Fsize=thumb
18:05:40.321 T:1946088096   DEBUG: Image /home/pi/Immagini/Palermo-Napoli 2017/DSC_0386.JPG is finished rendering, switching to /home/pi/Immagini/Palermo-Napoli 2017/DSC_0387.JPG
18:05:40.323 T:1946080176   DEBUG: CAnnouncementManager - Announcement: OnPlay from xbmc
18:05:40.323 T:1946080176   DEBUG: GOT ANNOUNCEMENT, type: 1, from xbmc, message OnPlay
18:05:40.325 T:1946088096    INFO:   msg: ExifParse: incorrect Exif header
18:05:40.543 T:1946088096   DEBUG: Loading the next image 8: /home/pi/Immagini/Palermo-Napoli 2017/DSC_0388.JPG
18:05:40.697 T:1723012016   DEBUG: COMXCoreComponent::Initialize OMX.broadcom.image_decode input port 320 output port 321 m_handle 0x71064720
18:05:40.699 T:1723012016   DEBUG: COMXCoreComponent::AllocInputBuffers component(OMX.broadcom.image_decode) - port(320), nBufferCountMin(2), nBufferCountActual(2), nBufferSize(4963104), nBufferAlignmen(16)
18:05:40.753 T:1723012016   DEBUG: COMXCoreComponent::Initialize OMX.broadcom.resize input port 60 output port 61 m_handle 0x71039628
18:05:40.755 T:1723012016   DEBUG: COMXCoreComponent::Initialize OMX.broadcom.egl_render input port 220 output port 221 m_handle 0x710d9e40
18:05:40.757 T:1723012016   DEBUG: COMXCoreComponent::UseEGLImage component(OMX.broadcom.egl_render) - port(221), nBufferCountMin(1), nBufferCountActual(1), nBufferSize(15360) nBufferAlignmen(16)
18:05:41.605 T:1731400624   DEBUG: CWebServer[8080]: request received for /image/image:%2F%2F%252fhome%252fpi%252fImmagini%252fPalermo-Napoli%25202017%252fDSC_0387.JPG%2Ftransform%3Fsize=thumb
18:05:42.871 T:1723012016   ERROR: COMXCoreComponent::WaitForInputDone OMX.broadcom.image_decode wait event timeout
18:05:42.872 T:1723012016   DEBUG: COMXCoreComponent::Deinitialize : OMX.broadcom.image_decode handle 0x71064720
18:05:42.874 T:1723012016   DEBUG: COMXCoreComponent::Deinitialize : OMX.broadcom.resize handle 0x71039628
18:05:42.875 T:1723012016   DEBUG: COMXCoreComponent::Deinitialize : OMX.broadcom.egl_render handle 0x710d9e40
18:05:42.876 T:1723012016   DEBUG: DecodeJpegToTexture: decoded /home/pi/Immagini/Palermo-Napoli 2017/DSC_0388.JPG 1619x1080
18:05:42.879 T:1723012016   DEBUG: Finished background loading slot 0, 8: /home/pi/Immagini/Palermo-Napoli 2017/DSC_0388.JPG
18:05:52.619 T:1946088096   DEBUG: Keyboard: scancode: 0x0e, sym: 0x0008, unicode: 0x0008, modifier: 0x0
18:05:53.210 T:1946088096   DEBUG: OnKey: backspace (0xf008) pressed, action is Back
18:05:53.211 T:1946088096   DEBUG: ------ Window Deinit (SlideShow.xml) ------

There are few errors, but I couldn’t find anything on the web that solved this problem, apart from some very old non applicable posts.
The only thing that I noticed is that a non negligible time lag exists just before the event “image xxx finished rendering”, but I don’t understand why.

In the end it is also worth noticing that if during the slide show I press the next button, the next picture get showed pretty quickly (less than a second) so I doubt this is just a slow rendering problem. It seems just that the slide show likes to be slow with apparently no reasons.

For now I run out of ideas, so please let me know your thoughts.
Cheers