[TYPO3-mvc] Image resizing in Backend Module

[Maurizio Monticelli]

Hi

i try to resize an image in a backend module. i always ge the error: "Call
to a member function getFileName() on a non-object in *
/xxxx/typo3/sysext/cms/tslib/class.tslib_content.php* on line *5320" *when i
call the IMG_RESOURCE() function.

in the Frontent-module this function worked fine.
in  the class Tx_Fluid_ViewHelpers_ImageViewHelper i saw also the
"ImageViewHelper does not (yet) work in backend mode"-excepition.

i there a general image-function problem in the backend?
how do i resize a picture in the backend?

thanks
mauri