I needed the functionality to duplicate items in Mendix. I noticed that there is a DuplicateImageDocument java action next to the DuplicateFileDocument but this one is not listen in the description of the Community Commons. What does the thumbWidth and thumbHeight do? Is this the pixel size I need to set? Or can this be automatically generated depending on the picture size?
That is the size of the thumbnail that will be stored together with the original image. This is usually something around 60x60 but depends on what/how/where you use the image thumbnails in your application.