Then use photshop simple as that. You asked what people use , I use that and it works.

And do you not re-size your images 1 by 1 if you use something else? Do you not go 1 by 1 to upload and download.

Amazing the reaction you get from some people when you try to help.

No, what I use are able to losslessly compress in bulk, drag a folder into it & off it goes!

As you can see, I have 13K files being compressed in that image.

You should probably be more specific next time you post a question like this and also be more careful of how you respond to others comments.

I took it your last comment as you saying my suggestion was worthless.

No worries mate, I only meant that as a comment about the gtmetrix thing, sorry if I confused you about that.

Cool, no problem ... And I am going to check that tool out for bulk re-sizing, is it free? A link to it?

http://pnggauntlet.com/
http://psydk.org/PngOptimizer.php

They're both free

I used IrFanView. It's a neat program. Does just about everything you need to do to pictures.
I use the bulk resize and rename quite a bit for my forum.
http://www.irfanview.com/