Sorry if this has been answered already (couldn't find anything about the specific problem), but here goes.
I've mainly used MP3Tag for well, MP3's. I've started ripping CD's and tagging FLAC files and for some reason, the image order isn't showing correctly when in a music player. The player chooses the album art as the image furthest down the list and I am wondering if there's any way for this to be prevented using the program. Kind of annoying expecting album art and getting the back cover instead.
You cannot set the order of images in a file.
You can set the type.
If the player ignores the setting for type ... you probably have to delete all other images so that only the desirable one is left.
It's not entirely true: the images are saved to the metadata in the order they're added.
Anyway, it would be interesting to know, if the player somehow takes the image type into account or simply relies on the order and takes the last one.
I've checked with Windows Media Player and Google Play's player so far. It looks like they simply rely on the order and take the last one as I have changed image types and still had it show the image most recently added. I guess I'll just stick with adding the front cover for now.
I don't use either of them, so I can't say definite things about their behaviour.
But you should take into consideration, that often players use a cache for their cover-art.
So simply changing the image types could not be enough to judge the behaviour.
Instead of changing already known files to the players just make a test with a new file that had no cover-art at all till now.