[TYPO3] FCE get Image width???

[Aji Johannes]

Hello List,
im trying to fix my problem with an Content Element (FEC) but with no 
success.
my Problem is that i have and Element and it only contain and Image and 
Caption for the Image. the image have Fixed Height and Flexible Width.
i want to read the Flexible Width value of the image and put it as 
Params or Wrap inside the <p> of the caption. like: <p 
style="width:|;">Caption</p>

this my typoscript inside FCE:
#field_image:
	10 = IMAGE
	10.file.import = uploads/tx_templavoila/
	10.file.import.current = 1
	10.file.import.listNum = 0
	10.file.height = 120

#field_caption : no typoscript

#field_imgwidth: ## as ATTRIBUTE

10 = TEXT
10.field = field_image
10.file.width = {field:field_image} # not working
10.wrap = width:|; # not working


do you have any idea???
many thanks for your Help

Regards
Johannes