If you want to shrink the file size further. Open the image in MS PAINT after you have resized the image in whatever software, and resave it. This reduces the file size and keeps image quality. It sounds strange but it works.
HP officejet 6500
Printer-HP officejet 6500
Software-Adobe CS6 desi...
Crop and resize the photo to what you want. Then go to file - save for web - this will bring up a new window. You have a couple of options to reduce the file size, usually JPEG at quality 60 works well.
The other way, make sure the DPI is set to 72. Save as a JPEG and choose a quality setting around 6.
Always duplicate the photo just incase you save on top of it self.
Another advantage of "save for web" in PS is that it removes all IPTC and EXIF info. Not only great for privacy, but it saves an extra 10-20KB that bears no image info at all. As to image quality, just play with the compression rate and watch the preview. Some pics are OK at 30%, some only at 75%. It's black magic ;-)
I don't know whether Irfanview removes the IPTC/EXIF on resize.
If you want things automated, like uploading an image to your website, and immediately e.g. let your webserver make thumbnails out of them, you'll need to find a host that has got the necessary components installed on their servers.
(like pbase.com for instance)
Ofcourse, this often doesn't match the image quality of photos resized by offline tools, where you have full control. And maybe more important for you is that you don't need to have any programming skills, which are required if you use these components, unless you buy a sollution which has it built-in allready.
Canon EOS 5D
Canon 70-200 2.8L I
Canon 50mm 1.8 II
I always depend on Photoshop as I find it the most powerful tool. The "save to web" feature is very convenient to use.
One note though, I find that many web designers are confused as to what file type they should save as. Photo images should be saved as JPEG while other computer-generated graphics should be saved as GIF.