When I look at the image you uploaded, it shows as PNG?
Make sure you save as bitmap(bmp), make sure it's 256 colours, and 8-bit, if you still have problems, i'll try doing it for you.
As for game audio, it's been a while since i've made my own audio files for WA, but it may possibly be the same reason some wav files don't work on phones and others do.
16 bit wav format works on phones, whilst 24 and 32 bit floats do not(the phones i've had at least), so try these different formats for WA audio and see if it works, start with 16 bit and work your way up.