I am attempting to learn how to publish research as an EPUB but when I place my draft from Word into InDesign, the resolution of text and linework in my png or jpeg images from PS loses resolution--gets pretty choppy and illegible while the base image resolution is just fine.. I am used to wrting in Word and adding images and publishing as a PDF from there. The text and linework of which I am speaking was added using the PS tools--the text is labeling and the linework is outlining added for purposes of clarity. It looks like i have a raster-vector problem? What's going on here and what should I be doing so the images will work in InDesign without having to try to add 60 labels in Indesign (which would be a textframe nightmare) and so I don't have to draw several versions of the same image for use in various applications?
You are correct that raster is the only data in your png and jpg images...I trust you understand why.
You can place native Photoshop (.psd) files into InDesign; jpg & png are not necessary, but type will be rasterized. To retain vector type from Photoshop, save as Photoshop pdf.
The captioning might be (better) done in InDesign.