wget -r --directory-prefix=/path/to/save/to -A jpg www.example.com/path/to/image/directory
All of the wget manual
The argument -Aallows you to specify file name suffixes that you care about (there is a similar one to exclude files -R):
-R - This is recursive extraction, so it will go to subdirectories.
--directory-prefix=/path indicates where to save.
And the flag -A, I will cut a fragment from the manual:
-A acclist --accept acclist
-R rejlist --reject rejlist
(. ). , - "*", "" [] acclist rejlist, , .