Hi Yannick, today I had fun modifying the source (delete and modified some configurations) of the "ZuneARC GUI" to create a GUI for the "PDFtoPNG" tool (I hope you didn't do something illegal), it was very tiring because I don't know Zune, but in the end it all worked. I wanted to include other utilities from the "XPDF-Tool" package, but since they all work on PDFs, with the same extension I had a hard time.
Yannick if you have time maybe you could create a generic GUI that is easy to manipulate so that it can be used for many other utilities without a GUI.
The GUI I created and it works very well, very stable, as shown in the Screenshot, PDFtoPNG extracted all the images included in a PDF document in PNG format and saved in the chosen path in filerequest, tested also PDFtoPPM, but as said I can't add it in the GUI, but I should create a second GUI.