WP image quality and workflow (use save for web?)

Ok…suppose you’re like me and:

-Baffled that WP re-compresses a lossy jpg into another lossy jpg upon upload and b/c of that…
-Want to establish a workflow that includes theme-appropriate cropping and using save for web for every image uploaded, maximizing load time for a mobile ready site. That said…

Is it best to preview and reduce quality as needed in photoshop, then upload? Perhaps after forcing WP to retain 100% quality (via a function) to minimize the effects of the 2nd round of compression?

Or is it best to do the complete opposite and have WP set the compression at 70-ish percent? I’ve looked into the ewww plugin but haven’t noticed a setting to specify a quality percentage. One would think it would be ideal to upload a lossless image format, then set WP to compress it in a specific way.

I hope someone wiser than I can shed some light, I’d like to do this right the first time. Thanks!