What tool do you use and can recommend for optimizing images that will be used in a website?
I have tried to use the images at the best quality possible in my websites, but they take too long to load and make the whole loading process of my site slower too.

If you are using Photoshop I'd use 80% quality JPEGs or 256-color GIFs. How large do your images usually turn out?

mostly, I re-save a Photoshop-created-JPG using MS Paint. Funny but its true -- it reduces the quality to a 1 bit per pixel; a 250KB can be reduced into 45KB. Guaranteed that web traffic will be smooth.

IrfanView Free and does batch rename / resizing

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