We would need to know about your workflow with the printer. Is your printer requiring CMYK files? That's a really old and outdated workflow.
The most common workflow is for the printer to request PDF files. If you choose the right PDF preset, the RGB files can be converted to CMYK the same way Photoshop does. But more modern printing equipment doesn't require CMYK at all because the conversion can take place in the printer's RIP (raster image processor).
Thanks Steve. I guess I am "outdated" with how I work It is just the way I am used to working. Probably 80% of the time I am sending pdf files for print, but sometimes I need to supply the client with a packaged file so they have everything, including all assets. I am just used to doing everything in CMYK.. Would you just import jpeg (RGB) into your workflow now then? Do you know how to control the pdf file size. If I import an image from Adobe stock through their workflow, it just comes in one size. If i have loads of images on a page, the pdf is likely to be very large. This is where I would use the old outdated style of making the image small in photoshop before importing into indesign. Thanks of r you help.
Converting to CMYK presupposes that you know what CMYK profile you want to convert to. It's usually a printer's responsibility either to provide this profile, or more likely to take care of this conversion themselves. And, like I said, your printer may have a RIP that does it automatically.
These days most people create layouts with RGB images because the printer can convert the images to CMYK, knowing what is the correct CMYK profile for their workflow. It also means you have the wider range of RGB colors available of you're displaying your output on-screen or on the web.
Regarding file size, I would resample the pictures in Photoshop to the size you need for the workflow you're using, if that is necessary. Then choose a PDF preset in InDesign appropriate for that same workflow.
Have you tried going to Photoshop, locating the images in your Library, right-clicking on them and choosing Edit?
I've found I can change resolution/resample, crop, apply levels and curves, and (probably) other edits, saving it back to the library. These immediately update their placed instances in InDesign. (Other PS edits, like adding adjustment layers, I can do but I can't save those changes back to the linked Library item, even if I try to flatten the layers. PS forces me to save as, unlinked, on my hard drive.)
There's not enough info around on this, I don't think.
PS That said, I do agree w/Steve that there's no need to do the CMYK conversion step before placing it into ID.
Thank Anne marie. I am fairly new to the CC library... I spoke with my printer who backs up Steve's reply... Thanks to both of you for replying.