Lossless image compression tools

[Thanatos_Prime]

We've had an individual or two doing some great work in the DB going through and using lossless image compression to replace a lot of overly large files with lossless versions that are significantly smaller in drive size. I've tried looking for good tools for this. All of them either seem to NOT really give lossless results, want to optimize the files in other ways including automatically making the images smaller in resolution\image-size or actually being a trial that will expire in two weeks and then they want you to fork over some cash.

What I want is something that will install on windows, it can be command line but if it requires having to install Linux or python subsystems I really won't ever do it. I'd rather it be GUI, I'll me much more likely to use it if it is. Ideally it would be free for long term use. It could also be browser based, but every one I have tried there has been a big let down on larger files. Whatever I use MUST retain the image resolution and size. I don't want to join the resolution ratio argument in any way. 

 Any help or recommendations would be very welcome. Thank you in advance!

[zetec-s-joe]

Fotosizer is a great tool, it's older now but I've always had joy resizing and such things

[Thanatos_Prime]

5 minutes ago, zetec-s-joe said:

Fotosizer is a great tool, it's older now but I've always had joy resizing and such things

To be clear the tool I need is a compression tool that will make the disk-size smaller while keeping the image size exactly the same. I don't believe Fotosizer does that...unless I'm missing an option somewhere.  I want to reduce megabytes.

[Thanatos_Prime]

I got one answer and that is this: https://www.imagesmaller.com/

Thank you for your time and consideration, everyone.