how to export image + type optimized for web with sharp type

I've tried to lay new type over the smaller image in Photoshop and that's not working either.

What's the pixel dimension of the Photoshop or exported ID page, and what's the point size of the type?

If you were to do a default export to JPEG or PNG of an 22"x15" spread, the exported pixel dimensions would be 1584x1080 px. Assuming the image is displayed at 100% in a non-retina browser, any text set at less than around 12px/pt would be illegible.

If the image is displayed in a retina browser, the browser will upsample and blur the text. In order to get the retina quality, the web developer has to provide a higher res alternate and load it via a CSS style. For those reasons it is not a good idea to set text in an image file.

Save for web? How?

What exactly are you doing and what version of InDesign do you have?

Try InDesign's Publish Online.

This online video tutorial will show you how (you can get a free 30-day trial to Lynda.com tutorials):

InDesign: Publish Online

Alternatively, assuming you have the Creative Cloud Suite, you could recreate your book as a website using Muse (if you know InDesign it's easy to learn): Designing a Portfolio Website with Muse