There a number of free re-sizing tools reading through write ups PIXresizer seems as good as any and I like it, but last year my original computer gave up the ghost and I had to download it on the new machine. I made a big mistake I picked some nasty spyware and a toolbar called sweetim, which was a nightmare to remove.
I had to remove everything I could find connected with the original download, but reading the good reports on PX I had a more cautious go at downloading it and found the site of the original author of the software.
I am now running it without any trouble. It is a great piece of stand alone software for simply batch re-sizing and putting the re-sized pictures into a separate file, from where you can upload smaller file sizes to photo hosting websites.
When installing the software make sure you only down load the PX zip file, do not let the freeware site install it and try to find a site that just lets you download the zip file and scan it with your security software. I opened the zip file to my desk top and read the text doc. read me. Here I found the address of David de Groots website;
http://bluefive.pair.com/followed the instructions from there, I think I am running it trouble free.