"The setting is set to high quality display. So there is no way to acces these files?"
The thing is that there are no files.
Just a bunch of pixels on an InDesign page.
If you want to save the stills to files you could do it this way:
[1] Export the InDesign pages to PDF (Print) with a PDF/X-4 export preset where you disabled any color conversion or image downsampling.
[2] Open the PDF in Acrobat Pro and switch to category Print Production.
[3] Click Edit Object in the side bar
[4] Select the image and use the context menu command "Edit Object…" to open it with PhotoShop
Save from PhotoShop to a file type of your choice.
Regards,
Uwe Laubender
( ACP )