I had tried to make batch script that copies all *.tif files located in D:\\images(random named subfolders here) to d:\\all.
xcopy D:\\Downloads\\*.TIF D:\\temp\
Searched files using windows file explorer for e.g. *.gif , I got files in search window, used Edit=>Select All , copy and then pasted to desired folder. This copied all the gif files in all sub directories to single folder. For large number of files, it sometimes hangs/not responding, but otherwise works ok.