If you have Microsoft office you can resize them in that program. this is for the older office programs. not for the new online version.
For those that don't know how:
1)find the picture right click and select open with, 2)then Microsoft office( not the picture viewer) 3)at the top click edit pictures, 4)at the bottom right click resize 5)select predefined width and height 6)use the drop down menu to select the size. I pick web large 7)click OK at the bottom right 8) from the file menu at the top select save as and pick a new name for your picture so you will still have the original. I usually just ad the word web to title so I know its ready to post. 9)when you close the program it will ask you if youwant to save the changes. say no. so that the original will stay as it was.
That seems like a lot to do but it only takes a few seconds to do.