The tricky part of what you're trying to do, seems to be related to correctly specifying the filename of the attached file (= the value to be stored in your
field-image field). For this, have a look at what is suggested in Comment # 25 of the support issue (not bug ...) #1431572 and which states that the correct way to do so is something like so:
Use Rules debugging
This question is pretty tough to answer with the limited info you provided (and without access to "your" site). Therefor, if needed, you might also consider some Rules debugging, by (temporary) enabling the Devel module, so that you can (temporary) add a Rules Action like "Display a value" (in your case of the entire node/webform that's used to submit that attached file). For way more details about such debugging, refer to Rules debugging, as explained in the answer to "How can I display the value of a variable inside a condition?".