I found on my 2014 ES300h that my system would only take one image at a time in the folder for it to work.

 

For me, the secret was not to use a folder called StartupImage. Once I got rid of that, it worked perfectly. The manual for my 2015 CT200h actually says that, but I kept seeing that I had to use a folder called StartupImage in all these forums. Wrong. So if you're having trouble, try putting your .jpg in a folder called Image. I'm on a Mac and formatted my USB drive as MS DOS FAT. Worked perfectly. Finally. Now if I could just get the voice recognition to work. If she says "Pardon?" one more time....