What i do is right click on a photo go to open with.
open a photo in paint,
at the top of the page go to image,
then resize then the top two % change from 100% to 12% in both horizontal and vertical.
if you want to keep the original photo size go to file at the top of the page and click on save as and change its name then save. this will keep the original and you will have a smaller photo for the web.
my original photo's are 4288 x 3216 pixles after resizing they are 515x386.
to check the size of your original right click go to properties then details if your photo's are smaller try a different %
hope this helps