change images in HTTP-Interface

[helpneeder]

hi!
after doing a backup of the 'original' HTTP-Interface i tried to modify the existing html-code to my special whishes:
+) i want to play only audio-files directly from my harddisk
+) the only functions i need are: play/pause and seek
(without playlist, video, streaming......)
+) playing new files is solved via php-script executing a command

it works wonderful!

further i wrote a php-script that converts my music-files in a .png-image.
(image looks like opening a music-file in an audio-editor)

now i want to place this .png (of currently played file) as a background-image of the progress bar.

it only works when i rename the 'wav_pic.png' to a filename that exists inside the 'VLC_v085\http\images'-folder

if the filename is not

delete.png
delete_small.png
eject.png
empty.png
fullscreen.png
........etc

the image is not displayed in the http-interface!

maybe somebody has a solution for me
thanks in advance!
(hopefully my english is understandable)