Find files not matching the posix extended regex '.+\-[0-9]{2,4}x[0-9]{2,4}\.jpg' in their paths under Folder1 and copy them to Folder2
find Folder1 -type f -regextype posix-extended \( ! -regex '.+\-[0-9]{2,4}x[0-9]{2,4}\.jpg' \) -print0 |  xargs -0 cp -p --target-directory=Folder2