refactored Image class; added checkFileForProcessing() function, which can also be used by the FM backend to check whether file processing is viable. This check is the exact same check as done by the Image class itself when transforming an image into a thumbnail.
refactored Image class; added checkFileForProcessing() function, which can also be used by the FM backend to check whether file processing is viable. This check is the exact same check as done by the Image class itself when transforming an image into a thumbnail.

cpojer/mootools-filemanager,cpojer/mootools-filemanager