ThinOS 8.6 - Can't change logo and wallpaper

I've uploaded the new logo and wallpaper files to the repo. Go into policy and change to the new files.

Reset the device and the logo and wallpaper download but don't display - shows dell logo and default wallpaper.

I can change it in 9.3 with a logo and wallpaper that were created at the same time by the same person. That works fine.

I did change it about 6 months ago with a slightly different file (the branding changed slightly so I had to revert it and wait for further approval).

I did try with the older version of the logo that's supposed to go on the 9.3 devices and that displayed fine, but was obviously the wrong size, so looks funky.

The graphics person can't see any difference between the new file and the old files.

I've tried manually resizing the files I have in MS paint to see if they were the wrong size. Didn't seem to work.

I told the graphics person that the logos should be 360x100px for the 8.6 and 420x110px for the 9.3. I have no idea where I got 360x100 from. Looking online now - it looks like max size is 352x80. The old logo files are 325x50. I've tried resizing the newer files to various combinations of all of that including just over and just under the max sizes.

Any ideas or suggestions? Anyone else had anything similar?