Why do you not use the Software Simulation feature of Captivate, probably the best on the market? It can be done in a responsive project, although it will need a lot more work to get it working correctly on all devices.
Just inserting images will cause you even more work if this has to be a responsive project. Do not underestimate that amount of work, it is not just about inserting images on a slide, but to edit them in each breakpoint view with Position Properties.
You use Photoshop? You can import a native PS file with all its layers. If you have multiple images in one PS-file, import it and all layers will be converted to a PNG image. Your work flow is really the most slow, indeed.
Be careful: since you are talking about bitmap images, for good quality you would need an image for each breakpoint view. PS can now export to SVG, which would make the quality approach easier, but I have no idea if the images you are talking about are suited for SVG export.