If you format your PS3 HDD, reinstall the game and its patches (and then the upcoming DLCs after the patches), and then you copy a backup of your save back to your system, the first time you load the game, all thumbnails will be either missing or wrong. Wrong can be anything, since a wrong color or missing bodykits/wheels on cars, or even wrong car entirely (text reading Renault Megane, and thumbnail is a Peugeot 207).
If you delete your save game file, and, before copying a backup of this save back to your system, you decide to load the game, it will create a "new save", right ? Then, once you finish whatever you wanted with a "new save" (testing something, or whatever), you quit the game, you delete your "new save" and then you paste your backup save back there, and the thumbnails will be all missing or wrong again, just as if you had formatted the system. If you delete your save (say, after sending racing gears to a friend, or tickets, or whatever) and copy the backup prior to getting back into the game (without creating a "new save" that is), the thumbnails seem to be fine then (although I'm not entirely sure of this. Sometimes I get the impression that by recreating a thumbnail after pasting a backup save back to the saved game data folder, the thumbnail's reflection is slightly improved, or the color, even though accurate, its hue is set back to its precise standards. Again, not entirely sure of these though).
Maybe there are other reasons for the thumbnails' glitch occurrences, but as far as I've noticed, these two (formatting, or loading the game after having deleted your save file without replacing it immediately with your backup save) always trigger this bug. Even though it is a long process, I'm glad they added the "create thumbnails for all cars" feature, 'cause doing it "manually", one by one was not fun at all.
but what are thumbnails in the game?
