Solved: Philips PhotoFrame ignores frequency setting for slide show

My parents experienced a problem with their Philips PhotoFrame (8FF3FPB/00). Although the PhotoFrame was set up to present photos in a slideshow with a frequency of 1 photo every 30 seconds, photos were only displayed for about 5 seconds, no matter what frequency setting was used. My parents use a Apple iMac, and I do think that some hidden files/folders copied by the Mac were causing the problem. After I removed (as a Ubuntu user) all hidden files, and left only the JPEG files on the disc, the problem was solved.Why?Among the hidden files were:Many .DCS*.jpg files for each photo contained on the disc A .Trashes folder with photos a few folders down the hierarchyOne .DS_Store file (typical metadata file that Mac's create to store And a ..Trashes fileI suspected that the .Trashes folder with 'trashed' photos inside were causing the problem, but I haven't been able to reproduce it by copying this folder back… nor with any other folder… anyhow, while th…