I spot 2 issues:
The 1st issue may be the one causing crash, but only because 2nd issue exists (although fix both of these and all should be fine!).
1) You call the function at start of layout, then call it again "on fetched". This would be an endless loop of running the function, causing the crash.
2) You store the URL in the dictionary with &world_Id, but then when you load from url, you use the iid of the object, maybe they are not matching up? Maybe ideal to use UID in these cases, and not use IID. The IID can change at times, like destroying an object, whereas UID will always be the same.
Im guessing you're loading many images at once in a loop, it should be able to work with right combination of events.
"Wait until previous actions complete" is very useful, but, may cause an issue for this case (it may not, but just a possible warning), as it may either: wait for ALL other actions, or, may load the wrong result into the sprite. Instead, it may be preferable to "load from url" then have separate event for the septiee "on load success".
Might be other things to consider but that's a start!