Problem with album art from SD Card

When I took delivery of my new Octavia 3 which is fitted with a Bolero a week or so ago I filled up an 8GB SD Card with music. When playing tracks some of them display the album art and some don't, showing only the rubbish SD card graphic. Thinking this might be an issue with the way in which the album art was saved into the file I took the card out of the car, put it into my computer and went through every track recopying the album art into them.

At first I thought this would be the solution because when first re-inserted into the computer, some tracks would show the album art on the file icon and some not, so I made sure that after recopying the album art every track now shows its art on the icon. However this has not worked and I still find that some tracks show the album art and some don't, seemingly on a random basis although if one track from an album doesn't show the art then the other won't either.

This is really annoying me! I can only imagine there must be some limitation on the size of the album art in the file that the Bolero can display. If this is the case it can only be very lazy coding on the part of whoever did the firmware - there is no reason why the firmware couldn't trivially easily scale a large image down to a displayable size. This is only a guess on my part, though - does anyone know the actual nature of this isssue and any solution? Or should I wait for a firmware upgrade in the hope that this pathetic limitation is fixed?