Sprint media manager question (WMA Album Art?)

I use Sprint Media manager to tranfer CD's to my phone.  This works for me because the WMA files work well with the rest of my family's mp3 players that are hooked up to the same computer.  Audio quality is good etc...

My question is how do I get the correct size Album art to display on the instinct for WMA files?

I've tried different methods and can get the correct artwork to work on mp3's and aac's but when I transfer using the Media Manager software the image shows up small on the phone. I'm using the  update, change album art option in the Sprint Media Manager software. The image is the same one for my test mp3 file and test aac file. The mp3 and aac display the 250x250 artwork image correctly.  The WMA file is small.

I've tested the artwork using it on different mp3's and it is definitley the right size 250x250.   

Thanks Z for responding to my post. I've been using the search function (for Months). I actually check this site often to try to get an answer that will work for me.

So far I've tried media monkey - doesn't work on wma but is great for mp3s and aac. I've stopped short of having my wma changed (Transcoded...whatever) to mp3.

Tried mp3tag.
Used Sansa art re-size. works well.

My problem is geting the correct size file to display on the phone on a WMA file. I'm trying to find if anyone else was able to get it to work with a WMA file ripped from a CD. I'm getting frustrated. Any replies are welcome.