Recommended settings to save disk space?

[C0080900]

What are the recommended settings for XnConvert to save disk space without losing quality?

I have hundreds of images such as .png, .jpg, .jpeg, .gif to convert and they are taking up a ton of space

So I'd like to know how to use XnConvert to disk space, help is appreciated.

[xnview]

If you don't want to loose quality, the best is perhaps PNG