Different functions in Java
I definitely prefer the second version. The steps taken just "leap out" of the code and the method is easier to read. It will also be a lot easier to debug (or to pinpoint the problem in a stack trace).

Always go for readability, it makes for easier understanding when going back to your old code and it's a lot easier for someone else to understand what is going on.

I also prefer the "data = fillImages(data)" if possible. It makes clear that the data is modified.