Low Quality Album Art - Android Q&A, Help & Troubleshooting

I've used two Android phones, a Samsung Galaxy Ace (2.3.6) and an LG L90 (4.4.2). Both phones have the same problem - their default music players compress the album art of .mp3 to undesirable quality.
I've edited the tags of all my .mp3 files with a 500x500 cover and every album folder has a file of the cover named 'folder.jpg', but this problem still persists.
The stock L90 music player has a very nice album viewer, but the quality is just hear-breaking. I'm looking if anyone has any solutions how to fix the album art quality. Here's a pic of how it looks right now:
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For those having the same problem as me, I could only find one work-around that fixes the album art on the actual player. It's manual work for each album, but it does appear to function:
---On Android 2
* Go to SD card -> Android -> data -> com.android.providers.media -> albumthumbs. You should find a list of files without extensions and with random numbers as names.
* Open each file with an image viewer until you find the album art you wish to change (it should take some time since you can't tell which file belongs to which album).
* Note down the name of the file.
* Place the high-quality album art into the folder and rename it with the name you noted down.
---On Android 4
* Same as above, only the location of the low-quality album art files should be on your internal SD card (on my L90, the location is /storage/emulated/0). Then it's the same: Android -> data -> com.android.providers.media -> albumthumbs.
The results:
This method does fix the cover of the album that is currently playing, but I have not found a way of fixing the art shown while viewing all albums on the device (first pic of my post). Anyone have any suggestions how to get them in high quality?
I know that most of you will suggest getting an alternative player, but this stock one is well-integrated with the device and has a very simplistic interface. It would be the perfect player if it weren't for that god damned album art!

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...soo, no suggestions? Or is this forum just a bit too crowded?

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I have Xperia M with latest Walkman (version 8.4.A.3.1). And the quality of album art is low. I have mp3 with high quality album art (embedded). I think this is android bug.

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Thanks for you solution! I think the player uses the same thumbnail for both. To elaborate, the album art of the song when you play it is the same thumbnail file as the album art when you go to the "Albums" page. However, though your solution works for when you're playing the song, it doesn't seem to work for the "Albums" page. I'm not sure if this made sense.