In the search panel .. You can select the files ..
then Copy > Paste (or Drag > Drop) from there.
CTRL+A will select all of them.
The problem will be that you will find a lot of Images that are not what you put in...
and are images used by the system and programs...
(Depending on what folder or partition you were searching in)
I'd suggest to copy them first .. then go thu the copies in the external .. and delete what you don't want.
Be sure to look for all the picture formats you may have used.
Are you going to organize a little better from now on ..