You specifically asked for Panels into the Gallery yet you created a folder under the 'Buttons' section.


For Buttons to show up, you need 2 images, a _P (Pressed) and an _R (Released) image.

For example, there are 2 files for CableTV under the folder:
C:\ProgramData\Philips\ProntoEdit Professional 2\Gallery\Buttons\Activity Clean Medium

These 2 files make up a button named CableTV in the Buttons->Activity Clean Medium category.

CableTV_P.png
CableTV_R.png


Not sure if Buttons allow file formats other than .png so if you don't have .png, may also not work

If you want Panels or Images, you need to create your category folder under the 'Images' folder and there I think you can populate with .png, .bmp, or .jpg