Is image resize the same as Lossless image optimization?

Is image resize the same as Lossless image optimization? I am looking to optimize images from my site so that the page speed is faster. I do not need to change the physical size of the photo. Will the pro plan with lossless image optimization optimize all photos and thumbnails on my site? Is there a limit to the number of photos and thumbnails that can be optimized each month? Do I need both image resize and lossless image optimization or just one of these options?

No, not the same. Image Resize does change the physical dimensions. Just the pro plan Polish/Lossless will do what you want. There is no usage limit for Polish.

I currently use Shortpixel to optimize my images. If I upgrade to the pro Cloudflare, I would no longer need shortpixel, correct?

One more question- I also use autoptimize-would I still need that plugin or no?