This is a utility to convert bunch of images to SWFs with the same size of images. You need to place the source.fla under c:\JSFL folder or you can edit the path of your fla in the JSFL file at line 35. Download it from here.

FLfile.copy(”file:///C:/JSFL/source.fla”,folder+’/Exported/’+tempName);

Also you can change the name of FLA/SWF accordingly from following lines.
tempName = “Image_0″+i+”.fla”;
tempName = “Image_”+i+”.fla”;