insert photo on with new record

All my other problems have stemmed form this. a new thread seemed correct since i may be able to ask a clear question now.

I want to upload a picture that goes to a dynamically generated folder. the folder name is the same as the record id that is autogenerated.

how do i get the new id number to create the folder prior to inserting an image into it?

I am stumped...the only thing i can seem to find is using some version of GETLAST, but everything I read says this can cause problems on a mutliuser environment.

$WA_UploadResult1_Params["WA_UploadResult1_1"] = array(
	'UploadFolder' => "./".$_SESSION['Dealer_Name']  ."/images/".$_POST["Inventory_ID"]  ."/",
	'FileName' => "[FileName]",
	'DefaultFileName' => "",
	'ResizeType' => "0",
	'ResizeWidth' => "120",
	'ResizeHeight' => "120",
	'ResizeFillColor' => "#FFFFFF" );

Inventory_ID is the the unique auto incrementing number i want to use for the new folder.

can this be done simultaneously(in the eyes if the user)?

Thanks,

David