ImageFromData to move from pygame to wx

I am working on trying to get a wx display to show image data that has been exported from the pygame module. The exported data is a string with the separate characters containing each part of the pixel data (RGBRGBRGB....). When I try to use the ImageFromData function to convert this string into an Image I get

TypeError: Type error. Got
                            ~???ջ?, expected _p_unsigned_char

I have been searching around for some usage examples that use ImageFromData to see what I could be doing wrong but have not had any luck yet.

Any help would be appreciated,

Andrew